Last week i boosted my 3x shammys from 15-40. I did stockades in 3 pulls from lvl 15-20. Then i did Cath/SM basicly as it is so small and easy to get around up to lvl 40. Fast as hell. But really mind killing... But atleast you dont have to worry about questing etc before later on when boosting wont be that effective.. so if you got a hunter id say you try that for as long as it works for you. But ofc.. you cant pull and then aoe 20-30 mobs down in a very effective way. For me as a feral my thorns made some mobs be close to dead by the time i got back to my alts for some swipings. And you gotta love Imp LOTP