My alliance has done some, and lemme tell you, things have changed.
Took 2 nuker parties, and one archer partie and 1 tank party to take out the RB at the Gm stone at the top of the snowy mountain and his minions had time to respawn.
I'm not really concerned with the lower bosses. The big issue is what happens with the S grade super parties now. Right now, a few dark vortexes pumping with gloom is endgame for all raidbosses. It will be interesting to see if this continues.
The higher-level bosses sure have gotten much harder than in C4.
After raiding Longhorn 2 times in C5, I can say that the raid farmers will have to increase their numbers or they will die to to the bosses.