i done in normal mode with my melee group.
found not good strat run around to each mob: wiped 5 times in this way.
good strat for me is keep group in coridor and tank at the entrance of the room: easier get/keep aggro on tank and have good control on mobs. basically my tank wait them, with dps behind him.
after all these waves, bosses look me pretty easy.
tbh no idea what boss nr.1 do, he dead fast, 2nd cast a lot of debuff, somenthing is magic (dispellable).
lich king final event with 5 paladins: i gone in "survive mode", with seal of light up and kept mobs facing away from my group: some mobs cast frontal cone desease, someones are casters, there are 4 waves almost same mobs, just some more in each wave.