I think the tanking is not the major problem, though we need someone with lots of FR for Onyxia and MC bosses after Garr --> Nuggy, Tom, Sanny would be my best bet according to
http://www.cybergings.org/raid/roster.p ... scending=1 (dunno if the numbers are up-to-date).
The bigger problem is in my opinion the loss of Inv as a raid leader. Few of us have tried to lead a raid bigger than UBRS so far. Gwen & Nuggy, Jevo & Tom, Zut & Nuggy and Dupa as far as I can remember.
If we have more than 1 leader in MC the raids will probably be chaotic.
Anyway, I think we should still go for raids and see what we can achieve. We just should set our goals lower than usual to avoid frustration.
So far we have MC up for today and tomorrow evening, Sunday afternoon and Monday evening. Onyxia would fit in on Friday or Sunday evening.