Well I didn't mean for this to turn into a discussion of gameplay!
Bastardbottle, I think the entire point of a dot class is to dot everything. Single-targeting seems suboptimal, especially in big fights, and is generally much better done with a pve hunter. (Which, btw, has much better tools to deal with mana...)
Mercy, granted, there's always room for improvement in how you position yourself, which is very important for ranged classes and especially those who play with pve gear. Unfortunately I have to rely on Dispersion/nitro boosts as an emergency button for several situations such as when a DK grips me or a rogue cheap shots/garrotes me, and no amount of peeling from teammates can help with that. A well-geared rogue (or one who knows where the Cold Blood button is) can kill me in two seconds (believe me, I've counted).
In any case, I will try to use Dispersion as soon as every fight is over and the coast is clear and during long fights I will continue to clench my fists.