So actually Aizen wasn't (that) evil when he wanted to kill the soul king, he just didn't have any other ways to reach his goal so he had to beat everyone who was standing in his way. Aizen probably knows everything about the soul king and knew that something like this could happen. So he basically wanted to save the Soul society.
The chapter is okay, there should be some explanation though. I don't understand for example why Ywach can't absorb things that can be simply crushed by Reiatsu.
And why is Aizen still in a chair?