Garothi: easy
Felhounds: medium->hard, depending on tanks knowing how to swap bosses across the room
High Command: medium
Hasobel: easy
Eonar: easy, people just have to know what order the adds are coming from
Imonar: moderate, 1 bad apple ruins the whole bunch because or trip wires
Kin'garoth: moderate->hard, once you figure out colors (red > purple > green) its pretty easy as long as people follow the directions
Coven: medium->hard, depending on tanks knowing how to swap bosses across the room
Varimathras: hard, until tanks figured out how to swap and then very easy
Aggramar: easy-moderate
Argus: medium->hard, depending on tanks knowing how to run to a bubble with a buff
Notice all the fights that are 'hard' have to do with tanks doing something that isn't drooling on themselves. Doing it on day 1 was actually painful because people are suddenly 'tanks' just so they can get into the group.