His bankai has always been like that, Tosen even specifically stated that exact same thing. Considering he's supposed to be powered-up by now, I think we can assume he should have some new tricks up his sleeve as what's the point of the moustache fire-eyeballed bankai stripping if, in the end, the only thing he can do is still using brute force?The only issue I have for his Bankai, isn't a huge ass target now? All damage taken to his Bankai....effects him, I think it was a dumb choice to use bankai.
My guess would be that his banka is immune to explosions or that he can absorb themHis bankai has always been like that, Tosen even specifically stated that exact same thing. Considering he's supposed to be powered-up by now, I think we can assume he should have some new tricks up his sleeve as what's the point of the moustache fire-eyeballed bankai stripping if, in the end, the only thing he can do is still using brute force?