Grimmjaw is most likely dead, he had his flashback and everything. The last time we saw him was what, two years ago? It would be lame if he survived.
I doubt it, but even so, don't forget; Urahara is still there.
And he is one of the least injured people, so he has enough strength left do deal with Ichigo. Ichigo doesn't even have any powers left, assuming his hollow side also "died". What the worst that could happen. (I say that now, but you never know XD)
We are saying that nobody important died, but we are forgetting someone; Unless something randomly happens, (Tensa) Zangetsu "died" for the moment.
Anyway, while looking stuff up, I found the reason for so few deaths. After Aizen owned all the captains; he said something like "I won't kill you. You're strong enough that those wounds probably won't even cause you to lose consciousness; so watch. Prostrate yourself helplessly and watch the battle."