Well first of all let me just say DAAAMMNN.....I was just starting to like Juha Bach as the main villain and then he got cut down all of a sudden.

My theory is that there is obviously someone else pulling all the strings and was just using the quincy as a distraction. Because Yamamoto's bankai couldn't be sealed unless it was revealed, Juha Bach and the war on Soul Society was a means for Yamamoto to reveal his bankai so that it could be sealed later on, and Juha Bach was just a sacrifice.

Whoever is behind this could have also influenced Aizen. There was never an explanation on how Aizen found out about the Soul King and the power of the Hogyoku. He even did this before becoming captain, so it is to assume that someone must have guided him and also used him as a way to reveal most of the other captains Bankai.

So perhaps quincy are not the only organization leading the conflict, but maybe a whole group of races(arrancar, ex-shinigami, substitutes, hollows, quincy, etc)

This is just a theory, so what do you guys think?