This opening is called "We Are ~ 10th anniversary version", whoever thought it wouldn't last long were just fooling themselves..more than likely it'll run for all of 2009 (till October?), when the anime is completing 10 years airing.
What makes you think that? Just because it's called that doesn't mean they have to run it for an entire year. An anniversary for something is celebrated only once, after all, not for a year straight. Besides, I see it like how we had the sadly short Brand New World replaced by the long drawn out Crazy Star. Except vice versa in this case. In fact, I have a feeling that we will see a new opening soon, in either late January or February, which will probably incorporate with the new filler arcs coming, and hopefully with upcoming manga events as well. Also, it better portray a certain someone differently after the events of this arc.
This version of We Are isn't at all terrible. Sure, I'd say it's probably the lowest ranking opening thus far, and can't compare to the other versions, but it's pretty catchy to me. One thing I'd really like to see though is the return of a normal opening/ending. :/ Probably won't happen though…
The only thing about this episode I actually liked was the foreshadowing at the end. But the rest was pretty boring for me. Next episode will be really good though. I can feel it.