Ichigo must be the soul king since he seems to master every faction's special ability just from observing it, in an annoyingly cliche shonen manner. He learned bankai in like 3 days, learned fullbring in 1 day and how to use the visored mask in a few days. All of those techniques others thousands of years(or most of their lives for fullbring) to master and Ichigo just learns it instantly. He's probably just the *** soul king. Also seems like he's the only shinigami to learn/know of his zanpakuto' full/true form(none of the captains even know how to use their final form or they would have used it before dying). Since Isshen know sabout final forms I wouldnt be surprised if he was a 0 squad memeber along with Urahara/Yorioichi and everyone else who's a ???-tier character and has yet to show their bankai.
Nah, if u think about it he didn't JUST master a bunch of ultimate techniques. It was the result of a lot of people spending a lot of years trying to figure out an easier way to get all of this crap done. And when you consider the circumstances of his birth and who his parents/guardians were, a lot of the stuff was probably made SPECIFICALLY for ichigo in the first place.
And wtf i've read the last 2 chapeters twice to make sure i wasn't skipping pages. I hate when bleach gets like this. Why, if i was paying money for this crap i'd be furious!