http://swtorblacklisted.enjin.com/mobile/forum/viewthread/m/4564953/id/20183564-arsenal-merc-rotation-how-to-shoot-stuff-in-30 some info could be irrelevant now, but i'm using these as guide for me merc. I hope they are helpful

Getting your abilities faster is a good point, but i'm currently leveling 2 chars with the boost and to be honest, it feels like i'm steamrolling trought the game, no more challenging fight(i know real challening boss fights dissappeared a while ago, but still, it was something) you have tons of story build up, convo wise, and then you autoattack and elite twice(yes, i am overexaggerating a little) and boom, you're a hero. 200% xp kills the story for ppl who haven't played it yet and i don't think unsubbing just to get a normal leveling experience is the way the problem should be handled. You should have a choice on how you level, bioware does need to think about that imo