Even with bankai, once you have seen kyouka suigetsu, the ability will still have effects on you and so it's useless to use something OP when you entire reality is being shifted as he pleases. That's the thing about aizen, you either fight him with all you've got at the beginning when you're certain that you haven;t seen his sword or get trolled.
Plus he would have regenerated form most of those bankais, maybe not shinji and uruhara since we haven't seen their's yet, but at the very best it would have the same effect as mugetsu which decreased his reiatsu significantly if I remmeber correctly