User blog comment:GinIchimaru/422: The Silent Victory - General thoughts and unanswered questions/@comment-3046295-20101001120530

I think you raise very valid points, however what we've learned of Aizen is that he regarded himself as one of the strongest Shinigami - and was able to mask his true intentions for quite some time, and his research wouldn't have existed if he had wanted to be a normal Shinigami. He was on the pursuit for power for greed, because he had theories on how it could be obtained, and being the analytical and interested person he is - he might have wanted Ichigo to progress because it would show him what would be achievable through natural causes - without the power of the hougyoku - essentially being a mirror to his progress.

Aizens loneliness might have arisen from the fact that he was the only Shinigami with the adequate ability to research as far as he was willing to go. Uruhara stopped himself from going as far with the Hougyoku - because its power although incredible, worried him and he attempted to get rid of it rather than do what Aizen did and try to utilise it.

He did say that he didn't trust anyone, and that he never wanted anyone to trust him, just to follow and he never really showed any emotions towards his sub-ordinates, even knowing Gin would eventually try to stop him.

Maybe Aizen wished that he didn't have the power he had, maybe he wished he didn't have a vampiric thirst for power - maybe that was what Kubo was getting at.