Voidwalker is pointless in raids, you're considered an idiot if you can't self-res in any serious PvE content. Raid setups for everyone are supposed to be Defender, Sunsinger and Gunslinger. Now these all work in PvP too, but Striker, Voidwalker and Bladedancer are all kind of pointless in a raid. Yeah you can nuke the boss with Nova Bomb, but so what? You need to be able to self-res to save your team the trouble of saving you if you go down, and also you can potentially prevent a wipe if you self-res at the right moment. As for why Hunters are the best CQC super, I don't know, the entire mechanic behind the Bladedance super does seem more fitting for a Titan, but oh well. They have to run around and manually kill their targets, Striker can just jump into a crowd and wipe out everyone, so I guess they balance out.