Bleach 310 (Canon)

[anime nomad]

I agree that they lost alot of the emotional content in the manga when ichigo lost his powers, and all for the sake of allowing the fillers to continue rationally. I suppose on the one hand its good that they care that the fillers are rational and flow on from the cannon material, even if they haven't cared about any of those details in the past.
Urahara seems to know alot about the process of losing his shinigami powers - my guess is that he is basing this on what happened to Ichigo's father.
It would be a really great idea for a filler if they tried to fill in the story of Kurosaki Isshin and his zampakto Engetsu. much like they filled in the backstory for vizards - that was not covered in the manga. Who did Isshin fight that required him to sacrifice his shinigami powers.
also, I'll have to find the relevant episode again, but i believe grimjow was killed by espada 5, (spent a good 5minutes here trying to recall his name with no success :O) Noitora!
Yami seems to be the only arrancar to have survived.