I've never had a problem with Heroic Azjol ... even this chain pull stuff with the Skirmishers. They are usually dead before they even do their "I'm not leaving this target" thing.
The end boss has caused a problem in one of the groups I was in though, those poison spitting mobs are pretty badass.
The worst heroic in my mind is Old Kingdom. I haven't really had a problem with ANY of the others.
I'm a fury warrior with Titan's Grip and usually run heroics with my guild (usually a pretty set 5 people ..... prot war, holy priest, fury war, blood DK, marks hunter or fire mage).
Things die so fast we don't have problems with anything usually.
http://www.wowarmory.com/character-sheet.xml?r=Trollbane&n=Sicar
That is me, haven't had great luck at all in getting heroics drops unfortunately. Start in Naxx this week, luckily I've done most of Naxx Pre-TBC ... so I should be able to just explain everything.