i liked Rosenbaum as LL. My issue with Lex Luthor (the most often portrayed comic version as opposed to MR's friend-betrayed/betraying version) is the delusional justification he operates under... that his actions are for the good of the world, because Superman is the ultimate bad-guy...
Batz can be very cool. Supes in NEVER cool. WW... has her moments (tho my favourite WW moment is in the Amalgam Marvel/DC crossover, where Storm completely fries the beyotch, and then in the "resolution" amalgam issue of Wonder Woman, Ororo has replaced Diana as Wonder Woman).
DC Universe is a different kind of MMO, so it might work quite well. Its available for the PS3 as well as PC, so its definitely not going to be the same type of MMO we're used to. Supposedly more action oriented. I suspect a lot of PUGs, and strict archetypes will become almost mandatory (even if their appearances vary hugely of course).