Here's my wall of text on the subject. I love the game.
When Dawn of War 2 came out, people said "Give us Dawn of War 1 with bigger army sizes (250 popcap!), more heroes and big crazy battles!"
So, they did. The scale of the battles is way larger than anything ever before and the elite system plays into the exact playstyle that people wanted. There is some pretty vocal whining, most of the complaining seems to revolve around three things: Power Core, No Sync Kills and Quality of Life features. : they wanted to watch cool super units engage in massive battles with hundreds of space marines and eldar and orks with tons of explosions and things dying.
I will address what the game is and my opinion of it, and then talk about these complaints.
The return to Dawn of War 1 mechanics: no retreat, no suppression, listening posts are back, upgrading resource nodes is back. However, many of the tactical elements that defined Dawn of War 2 are still around (i.e heavy weapons teams do AoE damage, rather than suppression, knockdown is still very important, Stun, blind, reflect and silence.) What has been pared back is the emphasis on persistence. Units are more disposable, with the only unit in the game that actually gets its own investment being Tactical marines. (Where you upgrade to either flamers or plasma on individual squads, and yes they are absolutely balanced around this.) Everything else is global upgrades or doctrines.
There's no leveling on either Elites or units. What this does is bring back a more traditional RTS gameplay approach where you can sacrifice units for damage, and in the late game being able to build units fast enough at home is almost a more essential skill than micro. We still have yet to see players truly use a proper macro playstyle, even in high level competitive play people tend to stop building additional units once they reach their "comfort zone" of micro, leaving half the popcap on the table. I think myself, Choko Bambus, VindicareX and Guruskippy are the only people that regularly prioritize them. They're either completely forgotten or a mid to late game afterthought to many other players.
The elite system is where all that intense DoW2 micro pays off. These guys are a bit more limited in what they can do than DoW2 heroes could be, but because of that specialization they also have some intensely powerful abilities. And the elite point system itself works as a timing push mechanic. I think most of the complaints of Elites being too powerful have fallen off as people have improved, and the more I play myself the more I don't consider them vastly superior to line units. Elites that are a little too strong have been nerfed appropriately relatively quickly. In the late game you mainly just want to focus on macro, splitting your army across the map and controlling your elites. Ultimately, I think DoW3's mechanics transition into a far more engaging late game state than DoW2's did, even though DoW2 has a stellar early and mid game. DoW2 lategame sufferred greatly from the victory point system. The old joke "Baneblade can't cap" applies here. Many late game units simply couldn't contribute to the win condition of the game in DoW2. I enjoyed victory points as a system that rewarded map control, but I think it was a very unsatisfying game mode for most casual players who had Autarch Kayle running lightspeed around the map constantly harassing their VP's while their Baneblade slowly crawled across the fucking HUGE 3v3 map to go fight... something. Power Core is ultimately more intune with this player mindset: Bigger units lets you fight your enemy behind their defenses and win. (And killing objectives rewards you with plenty of money to further bolster your army. I'll talk more about power core later though.
I think the elite system blends extremely well with the more casual take on regular unit control. There's still a ton of depth and nuance to line units, but at the same time it's a big step down from Coh2 or DoW2 levels. Which quite frankly is necessary when you're going to give players 3 heroes to micro and an army 3-4x the size of DoW2's.
Can I just take a moment and talk about what a great fucking job Relic has done with the actual DESIGN of the Elites and Factions in this game? Holy shit, it is such a massive improvement over everything they've done. (And I adored CoH2's new factions designs with Western Fronts and British Forces) Every race has unique mechanics that make it feel really different, and similarly all the units feel both useful and slot nicely into the factions arsenal. Does no one else remember what a shitshow DoW1 and DoW2 could be in compeptitive play, especially before Retribution came out and largely balanced DoW2? DoW1 drastically favoured ranged units and kiting and my limited experience with the game around 2007-2008 was Necrons being insanely broken. DoW2 at launch had all sorts of problems, like Tyranids being massssssively overpowered. The factions in DoW3 don't have this problem. DoW3's factions are the best designed content they've ever produced. Space marines are slow and can't really relocate around the map very quickly, but can call down drop pods to bring units into the fight right away to bolster their forces, and they have their Chapter Standard ability to either commit more fully to an engagement or to run away. The deathstorm drop pod also helps them in this regard, inflicting insane DPS and being able to turn the tide of many engagements when used at the right time. This contrasts heavily with the Eldar playstyle that is all about taking full advantage of your shields and fleet of foot to disengage after doing some damage to go teleport to the other side of the map and attack there. And then Orks. THE FUCKING ORKS. Holy shit I love their design. The Waaagh towers signal an attack as an entire Ork army runs across the map to fight with bonus speed and damage temporarily, the scrap system means that Orks can unlock abilities for their infantry or even build vehicle units from the wrecks of enemy vehicles right on the spot. Instead of the rooted concentration of forces of space marines or the extremely mobile Eldar, instead Orks are all about dictating the ebb and flow of combat.
And the elite units are similarly incredibly well designed.
Each faction has 9 elites, every single elite ability has 2-3 functions. The easiest example to give is Farseer Macha. She has three abilities: Singing Spear, Psyker Blast and Temporal Weave. Initially these abilities have their obvious purpose. Throwing the spear damages and knocks down enemies in a line, Psyker blast causes a defensive explosion around Macha to damage and knockdown units around her and Temporal Weave works similarly to Phase Shift in DoW2 and removes units from the fight along with the Farseer herself.
But then there's the secondary effects. The spear thrown into the ground debuffs nearby enemy units, causing them to take more damage. Psyker blast also applies Fortune to Macha, giving her bonus damage and damage resistance. And lastly, the singing spear can be recalled to again damage and knockdown enemies it passes through. When Macha has cast the spear, her melee damage is also massively reduced.
But wait, there's more. Throwing the spear into the ground causes both Psyker Blast and Temporal Weave to behave differently. Instead of psyker blast being a defensive ability centered around Macha, when you throw the spear it becomes centered around the spear. This can be used to either damage enemy units or to give allied units the Fortune buff. (Or buff, if they're all standing in the same spot.) Temporal Weave will be projected along a line between Macha and the Spear, rather than in a circular AoE around Macha.
But wait, there's even more. All the Elites can come into battle with an Elite Doctrine, which is either a "Command" ability (in effect for the entire game) or a "Presence" ability (only active while the elite is alive). The commands are usually some sort of unique buff. In the case of Macha, it allows Wraithguard to increase their attackspeed while draining their shields. Macha's Presence ability lets any of of your elites have a second chance at life when they die, restoring roughly 33% of their health and putting them in stasis for a few seconds.
Every single elite has this kind of depth, and they all work within the existing faction mechanics. Eldar elites have shields which can regenerate in webway auras while Ork or Space marine elites have to retreat to a production structure to heal, Ork Elites can utilize scrap taken from the fight. Space marine elites tend to have abilities focused around staying in combat for a prolonged period of time, such as Diomedes Zeal and Fury or Jonah's attack speed buff as he casts spells.
P.S They've also fixed special attacks. Instead of the archaic melee skill system, now heroes use special attacks or critical strikes every X amount of regular attacks, indicated on the HUD. This allows you to know EXACTLY when a special is going to trigger and you can take advantgae of that tactically.
Army Doctrines work like a suped up version of CoH2's bulletin system. You have 3 slots to pick various abilities that benefit different units in your army. Some simply give units more shields, or additioal effects for existing abilities. Some give them entirely new abilities. Some are passive, some are active. Ultimately, I think doctrines are a huge improvement to the 3% more weapon accuracy bullshit that was in CoH2 and it allows you to experiment a lot with your own playstyle and how you incorporate units into your army. For example, Banshees have a doctrine that lets them reflect attacks when using their unlockable charge ability. I've been using this to reflect grenades and powerful ranged attacks back at the enemy, which is hilariously powerful and very reminiscent of the cool micro tricks in DoW2.
The base building in DoW3 is straight forward but I'm hesitant to call it simplistic because placement of buildings is really important. It reminds me of C&C or BFME2 in that regard, it may disappoint Starcraft players but everyone else shouldn't be complaining. In the late game, building multiple production structures is actually worth doing to keep pumping out units fast enough which is a first for a Relic RTS. There are minor differences in the factions here as well, for example the upgrade structure has a different price for each faction and the Ork tech tree is very different from Eldar or SM. The economy model is also pretty nuanced, because generators take such a long time to build and you can only build 1 per node at a time you have to be very particular about which one you want and when. I think there's a ton of unexplored depth when it comes to this area of the game in competitive play. The elite point generator is also a fascinating thing because its resource cost changes based on the amount of generators you have. In some respects, the elite point generator and the lethality of elite units is a comeback mechanic. If you're losing some line units early on, if you can get an elite out and use it well enough you can get back onto even footing.
So, lets talk about the elephant in the room. Power Core. The community HATES this game mode. I imagine a lot of this has to do with the fact that most players play team games, where the game naturally starts to form more "lanes". There's also the matter of people overestimating the kind of army they need to kill a turret, and so I think a lot of 3v3 games mostly devolve into "fight until late game, one team gets resource advantage and builds more late game units, attack move at each other until one side wins the tug of war". Essentially, I think that the community is literally too dumb for this game mode, atleast for now. They don't realize how early they can actually attack the enemy objectives and you can hop into most random 3v3 games and carry your team to victory by bashing these things with a smart army composition. In 1v1 people have really started to figure it out and I think most people enioy it, but for team games annihilate is much more the pace of what the community wants.
Sync kills are gone. It's an odd time to do it, since line units are more expendable than ever, but it has been an absolutely constant criticism of their previous games that things like sync kills, cover and squad formations were huge headaches for people. I think the game still has some really awesome looking stuff to replace them with the elite units, like Wraithknight Taldeer's Jump ability, so I find this to be one of those grass is always greener complaints. The game still looks very awesome in action when big armies fight it out.
The other complaints are mostly quality of life features. Observer mode, customizable hotkeys, some UI stuff. This game launched with the usual Relic fare: no hotkeys and mediocre replay features. Nothing new. The UI is the best they've done though, in my opinion.
I think what makes people dislike the game is that the way they want to play it (sit back and build up a big army) is not really how it is meant to be played. You're literally meant to be throwing your units at the enemy and fighting them for the first 20 minutes while you're getting a huge refund for any losses. Building generators early in DoW2 was pretty common, but in DoW3 overinvesting in generators out of the gate is what causes people to have small armies and lose fights. The economy is simply way more complicated early on, and people are a little too timid in the early game. (especially in team games) Like how Para said he thinks the game is punctuated by lulls in the fighting and is a slower game than DoW2. I don't think it's slower, the lulls in combat aren't any longer than DoW2's retreat lulls. The difference is that people are playing passively because victory points used to work as an incentive to go into the field, whereas power core encourages defensive play until you are ready to take on your opponent. However, when people 'feel" ready and when they "are" ready are two different things, causing players to spend minutes sitting around doing nothing in 3v3. I think this, more than anything, is what causes people to get bored of the game and feel like every game plays out the same way.
tl,dr
DoW3 is an incredibly well designed game. It is very different from DoW1 and especially DoW2, but that doesn't mean it is bad. All of the same criticism that can be leveled at DoW3 was leveled at DoW2 when it came out.
The playerbase being what it is has almost nothing to do with the game itself. Modern PC gamers either play singleplayer titles, or they play a select few ultra-popular multiplayer titles. If your title fails to achieve ultra-popularity, it's going to have dismal player numbers until it goes through several waves of steam sales and builds up a dedicated playerbase. This is especially true of a niche genre like multiplayer oriented RTS games. Nostalgia goes a long way, as can be seen with Age of Empires 2 HD.
Here's DoW3's playerbase up against some recent multiplayer focused titles (jun23 and prior is pre-steam sale discount)
http://imgur.com/a/hzzVGand Here's DoW3 up against the biggest RTS releases of the last year or so that aren't remasters.
http://imgur.com/a/bUcg2http://imgur.com/a/sKabA