User blog comment:Flamesword300/Overlooked? Ichigos true strength/zanpakuto discussion/@comment-5681812-20130621063411/@comment-11051098-20130622094504

Or at least had monstrous reiatsu at the time, after his first 2 transformations through the Hogyoku. I thought in the line of what I wrote in the post you replied to, but I got a better view of things while discussing the same thing on the forums.

It really does seem like the reason Ichigo was able to defeat Aizen was that he did gain a monstrous level of reiatsu himself, after the Dangai training, instead of discarding it like Aizen thought. He probably gained a level of reiatsu so immense that even Aizen became unable to feel it.

Concerning the topic, I don't think his reiatsu now, after unlocking his true power, will be that immense - I see his post-Dangai reiatsu as a temporary power boost. But it is likely that he will have a much higher level of reiatsu with his true power unlocked, than what he had prior to the Dangai training.