2 of 2 there is no need for the tag in the header

Why was the ending to the Arrancar arc so brief?

I started watching Bleach probably a month ago and quickly found it to be quite interesting. But there are some things I just don't get.

For example Aizen... I thought Aizen was awesome. He commands such awe, attention and fear and you can tell that from the Shinigami's protecting Karakura town.

But I don't get is reason for being.

As far as I remember, every villain that Ichigo came across and defeated - at least the fairly important ones had a background story.

To digress Grimmjow, Barragan, No 1 and 3, 5 (+ Neliora) Espada's etc.. had a "beginning".

Disappointingly, Ulquiorra (my favorite Espada - btw) had none.

Kaname had a reason for being. Even Gin - also another disappointment imo - had a beginning, despite its vagueness.

But back to Aizen - from the very beginning he was just someone that had twice the amount of reiatsu when compared to a Captain level.

From what I got he simply wanted more power. To destroy the soul king and in turn destroy Soul Society.

But what happens after that? He obviously finds Hollows insignificant, he hates the Shinigami but we don't know why.

I'm not sure if many people feel the same way but there just wasn't enough back story as to why Aizen is.

In the end all we got was some speculation from Ichigo - that doesn't really make sense btw - about how Aizen felt lonely because no one matched his power.

So to find an equal Aizen groomed Ichigo's powers, but the funny thing is Aizen, according to Ichigo's speculation in the meantime sought more power by subjugating the Hogyouku to his will.

If he had so much power, and he felt lonely simply because he outclassed all others, why not find a way to suppress if not completely get rid of his powers akin to Zaraki's eyepatch?

Ichigo speculates that maybe Aizen let go of his sword willingly, but in Room 46 he doesn't look like someone that gave up his sword "willingly".

The "explanation" that we get from Ichigo sounds rather similar to what the author gave us about Jin Kariya. But there was a reason for Jin's motive and considering his back story the explanation for his defeat does make sense.

But Aizen... I just don't get it.

If anyone can make sense of my question, can you give me a satisfactory answer? :P