I want Aizen to return, but what does his return have to do with Central 46? Aizen was last seen in Muken, which is located beneath the Squad 1 barracks.
Aizen hid in the Central 46 WAY, WAY, WAY back during the Soul Society arc and has had nothing to do with it since then. Maybe Kyouraku is going there for a totally different reason. Knowing Kubo, it won't be to see Aizen, which is what I wish it would be. -_-
Although, I suppose Kyouraku could be heading to C46 in order to ask permission to use Aizen, who is located in Muken, as far as he knows. Does he need to go there to ask for permission if he's in charge of the Gotei 13? I just doubt Aizen is still there, and asking to use him would be stupid. Aizen would just take over the Seireitei, even if he succeeded in getting rid of Juhabach.