Dawn of War Codex

Space Marine terminators, as you all know, have 3 special weapons; an assault cannon, a heavy flamer and the cyclone missile launcher. I seem to see the cyclone missile launcher a lot more; this may be because all I see of Elite are Indrid's faction wars and the splash damage would be more valuable. So I'd like to ask; when should I get each weapon, and when are equivalents, like the tactical space marine flamer, more economical?

PS. In which cases would the terminator force commander be effective?

The missile launcher is great if you have low/no AV since it's quite capable to kill a FP/pred on it's own if it fully hits, and even if it doesn't it does good damage, coupled with it's long range it's also good as a finisher for a vehicle that's running away, it also brings decent distruption and anti infantry damage, so I would say it's the most general upgrade you can get and will always be effective.

The flamer is more specialized, you may want to get it vs IG sometimes although it's extremely risky, widely a good choice vs nids and orks, especially for it's ability and especially if they have big melee blobs, still a very risky upgrade which may lead to the death of the squad, but it's also high reward for the damage it does.

The AC (assault cannon) is in a very good spot at the moment, it helps in suppressing or may suppress in 2-3 full volleys (I don't rememer the courage damage it does now) it has a great single target damage and it wasn't decreased in the last patch like the standard weapons of termies, so it remains amazing vs high HP low models squads, heroes, subcommanders.

Now that you know this, choose the weapon around the situation you find yourself in.

Ace didn't mention this but generally speaking the terminator fc is never better than standard fc with wargear and levels. Esp if you have a level 8 fc by the time its economically feasible for you to put him in armor.

The time when you should invest in him though is when you have chosen to invest nothing into wargear and your fc is not really leveled. The terminator armor gives him a bit of a boost to make him more viable.

You can give him a flamer to do the same thing as what ace suggested you do with the standard termi squad except you can get away with more risky stuff since the terminator fc just needs heals, not reinforcements.

More follow-up questions.

When is the assault cannon more effective than using a devastator squad? When is grabbing the heavy flamer more efficient than using the tactical space marine flamer? When is the cyclone missile launcher better AV/artillery than, say, a Whirlwind or a plasma cannon devastator squad? Is there a particular weapon that I should go for by default? From what I see, all 3 are straight upgrades from the storm bolter.

The assault cannon and the devastator heavy bolter serve different purposes. The assault cannon is a dps boost on a squad that already has very good dps, doing over 100 piercing dps even in spite of the slight storm bolter nerfs. It happens to do courage damage as well, but suppressing isn't really the main reason for getting it. You get a devastator for the control you get through suppression, but its damage potential is never anywhere near that of a terminator squad.

A tac flamer is primarily an early game utility purchase, usually either for bashing generators or as a garrison counter. It is usually replaced in tier 2 by either a missile launcher, plasma gun or sternguard veterans, long before Terminators are even available. The heavy flamer does much, much more damage than the tac flamer, and is mainly purchased against Tyranids and Imperial Guard for use against squads that have a lot of models, but low health per model (guardsmen, termagants, catachans, etc.)

The plasma cannon is especially good when you have a surplus of requisition but not much power. It's good for denying VP's and doing massive damage to whatever it hits, but it does not have the wide spread of the Whirlwind or Cyclone missile launcher. The whirlwind has a wide spread and disrupts a lot, but does very little damage. Both will be available long before you can get terminators. Another key difference is that these two units do artillery with their basic attack, while the cyclone missile launcher is an ability-based weapon with a 40-second cooldown.

Both the assault cannon and the cyclone missile launcher are straight upgrades. The assault cannon is a straight damage buff, a range buff, and also gives you a little suppression. The cyclone missile launcher is probably the best overall upgrade, since it adds several dimensions to what terminators are capable of, while not losing anything. These dimensions are AV and infantry disruption, both at very long range. The heavy flamer is not exactly a straight upgrade since it has roughly half the range of the storm bolter. Any attack orders you issue to a heavy flamer terminator will force them to close to the range of the flamer, and if they stay out of flamer range, they won't be doing as much damage as a terminator squad with 3 storm bolters.