Ive noticed alot of people have focused on their disgruntlement with the explanation of the hogyokus powers and about how Aizen downsizes Urahara's knowledge of it. However we have to accept the fact that for now this is how things are. This is a 'What Now' speculation blog where i hope people will comment on what they think Aizen will do with the hogyoku and this new power (and yes it is new to him as this is the first time he has truly mastered the hogyoku). I'll give a few possibilities:
1) If it truely materializes the will of the master, then surely the most logical thing is that it will materialize the kings key, or something else that will give Aizen access to the kings dimension.
2) Aizen will instantly be able to kill anyone he wants.
3) It will give Aizen some sort of power over Ichigo.
Thse are just starters, im sure you smart folk out there will have some good theories/insights into the use of the hogyoku by Aizen so please leave them in a comment below, Thankya.