I didnt notice much difference stepping up from normal to heroic but my team is pretty geared. People talk about purging on the champions but I have always just focus fired them down Kill order always Rogue > Mage > Shaman > others. As for Paletress I just have staggered tremor totems (cast 1 each second) Then my guys very rarely get feared and if they do its for less than a second so its a quick reface and carry on.
Black Knight is the only boss in there which requires more than 1 button spam and all I do is heroism at the start of phase 2 and drop earth elementals. If you strafe away from the zombies as soon as he dies in phase 2 and go into phase 3 with everyone alive then its pretty much impossible to wipe. Ive done the whole of phase 3 with just a healer and tank before though.