I'm not as far as heroics yet, as I'm not yet 80 on all the guys, but I haven't had any issues so far. Heroics just throw out more damage and have a few more tricks to watch out for, but not really leaps and bounds higher in the difficulty department (managing all the characters, that is). I'm actually looking forward to starting off with Heroic UK, as it seems like it wouldn't be too bad to box.

I think most people would agree that heroics have more to do with a gear check than a team makeup, so long as you have a tank and a healer.