Just a small example, one day I've seen a gunnery commando dps in HM TC in full 180, he refused to attack adds ("because I do a lot of damage, I'll concentrate on the main big guy"), but it didn't stop him from using Mortar Volley (expensive aoe attack which would fit perfectly for attacking adds, however he used it on the main boss).
To be fair, Mortar Volley should increase a Commandos dps even in Single target situations. Its damage:ammo ratio is very similar to the damage:energy ratio of Orbital Strike for Snipers and they use OS on single target quite successfully. But Snipers can do so without messing up their Energy management, Commandos probably can't, I never tried it.
And of course Mortar Volley would be far more effective on the adds.
Weird people story: I did a Cademimu HM run on my Powertech tank. The damage dealers of my group were a Advanced Prototype Powertech and an Assassin (don't remember the healer). The assassin had the very inconvenient habit to use his knockback on cooldown. He would kick the enemies:
- away from me just before I was using Flame Sweep
- out of my Oil Slick
- out of AP PTs flamethrower
- never over a cliff.
After the second trash pull the AP PT asked the Assassin if he could stop using his knockback, since it made it difficult to fight. The Assassin responded (paraphrased):
"Yeah, but it deals good damage."
Now, I didn't check on my Shadow, but I thought the knockback requires a GCD and since it doesn't synergize with any dps tree at all, there should always be a better option than using the knockback (dps-wise).
So he continued kicking and then we reached the second boss. Those 'cute' little Ugnaughts are not immune to knockbacks. When the first group of them came down flying I could hear the familiar sound of a certain Assassin skill and the Ugnaughts were spread apart before the even reached the ground. Since everybody was rather close to the boss, I could use my Oil Slick and aoe taunt to get them a bit under control, but it was annoying.
Of course the adds had to get killed first and after a while I could hear the second group of Ugnaughts flying down...
Again they were flying in all directions and away from my Flame Sweep. Sadly the Ugnaughts didn't even go for the Assassin, but for the AP PT and the healer, so I felt obliged to get them under control.
Yeah, I didn't understand what he was hoping to gain from his constant kicking.