When the situation will get the worst Aizen-sama and my man Kisuke will pop up with their bankai and roflstomp Juha.
Abit seriously: Well it's hard to see any major threat to Bach atm. I can indeed see Kyoraku went for Aizen. If that would happen, with Aizen in the gang anything can happen. Can also imagine Ishida turning against Bach at the right moment, temporarily doing an opening , not much chance for that tho.
Got few more theory but non of them is certain, anyway i just hope it won't come down to some bullshit, and in the end he will regret what he did so far and surrender, i'd rage with a scenario like that.