I had my rogue grind 80-85 in his 277 ICC heroic gear.. it wasnt bad but for awhile (not sure if current HB does it) the rogue would hop up and down in between pulls, and I had him in stealth in between pulls so he would end up attacking other people's mobs (attacking mob out of stealth at same time someone pulls it).. but he still leveled pretty fast and never died. Just the hops were real obvious, and in BGs (botted him to full bloodthirsty) the click to move would be obvious, it would click right where the person WAS, so he'd get to their previous spot and stop, then click to move to their next, infinitely kiting my rogue as he bottishly clicked spot to spot.
Yeaah. Havent tried the new BG bot thats out, this was about 3 weeks ago.