Re: unresolved plot lines
I want to know what's going on with Ishida's dad also. We haven't seen anything of him since he trained Ishida to go to Hueco Mundo, and right after Ishida snuck out Isshin stopped in and the two of them chatted like old buddies. That didn't really make sense seeing as the Shinigami and Qunicy don't get along very well, with the exception being Ishida.
It's all about the symmetry.