On normal mode its quite easy, but on heroic it is the only instance I skip. I simply can't get passed the 3 heroes in mount without wiping 10 times min. I tried every possible way that was mentioned in this thread but I simply can't get it right. With all the repair bills + time taken, its better off wait 15min and get another random.
try my "strategy of center". it s a lot easier. run to mounted champions in middle area (aka engage them in middle ASAP, moving to them). if you do it right they dont charge