At Blizzcon they confirmed that Icecrown Citadel will have 12 bosses. Arthas and Sindragosa (the dragon on the login screen) will be two of them.. but that leaves 10 more.
I’m pretty sure that
Garrosh(ok, not Garrosh.. what’s his name.. ), the guy who got his soul sucked into Frostmourne at WrathGate will be one of them.. but who else?
Also wanted to add.. I’ll be surprised if we don’t face the following:
– Epic OMG-too-many-to-count army of scourge (probably another version of the “trash” before Flame Leviathan)
– An army? or at least a bunch of the big stone Vyr’kul guys.. like the ones under the walkway in Halls of Lightning.