BMW has had fast riders capable of winning races, the bike just seems to be missing something that prevents them from doing that in WSBK. And I will predict it gets its butt handed to it in Superstock by the Panigale too.
Is it better than the Aprilia in World Superbike trim? I doubt it. At best it is equal.
Is it better than the Ducati? Probably not, the Duck with Checa will be formidable again this year.
The changes to the BMW for its facelift for the 2012 model year won't really do much to help the Superbike. IIRC they finally dumped their own in-house electronics for Marelli. That is probably a positive move, although this also removes any opportunity to be better than the field too in this area.
Melandri might win a race or two this year, but I would be very surprised if he is in the championship hunt.