This filler arc might not be so bad, Ichigo and Co. fight several successively stronger but seemingly random enemies (mystery Hollows) in an effort to find a lost female (Rukia) and behind the back drop of trying to find her there's some kind sub plot going on (Weird Shinigami backstory) which we find out in the end makes all the fighting seem understandable. It's worked before...

My only concern is how this will affect the overall storyline when they pick back up where the mange went. I think we could probably without any more extraneous filler characters sticking around after their arcs are over.