Good point there Uno...the animation quality has definitely improved. Though, I'd rather not think that's a sign of the filler arc ending. I just don't want to set myself up for a bigger fall if it's false >>
Looking back on things, I think initial excitement blinded me and my fanboyness. If this was truly the opening to the Vizard/Arrancar arc, there would be clear images of them. I think that's only fair to assume. The opening hints at a few things, though it's too early to say.
And Xero, I agree with you 100% here. Tatsuki is such an ignored character up to this point, it just bugs me. They keep showing her every so often (e.g her confrontation with Ichigo at the school, and of course his secret being revealed in the underground base). It's one big tease so far.
Finally, we can only guess at who will come assist our trio of heroes. Obviously, they can't touch Aizen. Heck, Grimmjaw could cause them trouble, unless Ichigo has grown even more in the spiritually rich environment, Though that works both ways. Odds are it'll be someone from SS.