Ichigo getting his powers from the pit seems too obvious. And if we just learned anything from Bleach, it's that the least obvious is most likely.

I know there isn't much evidence to my theory, but then again, what evidence was there that Aizen was the main villian? I'm just trying to look at this outside of the box. I always thought the pit being the source of his hollow abilities was too obvious, even before the Aizen twist.

Yes, I am aware that he had powers before Rukia was involved. But so does his sisters. Which leds me to believe the source of those powers came from heritage of some sort, and seeing how his dad is completely clueless to the spirit world, it is most likely his mother. Possible that it's somewhere else down the line, like grandfather or something.

But even then, when Ichigo gains Shinigami powers, he was too powerful. Everything up until now has just been him understanding how to wield all this power. Even when Renji and Byakuya came to the Earth realm to take Rukia, he didn't fully understand how to use his power. If he was able to use his Soul Slayer's ultimate attack he most likely would have beaten them at that point.

He technically hasn't gotten stronger, instead he's just learning how to use all this power that he has. This power was given to him when Rukia transferred her powers over to him. Like I said before, yes he was able to break the binding spell, and yes he could see spirits, but that just meant he was well connected to the spirit world (possibly even being Kaien's reincarnation.)

When Ichigo actually escaped from the pit, his eyes glowed firecly like a hallow in the dust, as well as the mask forming. While everyone assumes that's when the Hallow form attached to him, I think it was his Hallow form being able to take shape, and escape, whch would explain why he looked like a hallow upon exit (glowing eyes and all.)

Again, I don't have much evidence, just major speculation, but I feel that it does still fit and it's the most obvious answer, which what I think it isn't. So I might not have much evidence, but then again, what evidence was there about Aizen?