Spoilers....




























The fact that its so small is what makes Ichigo UNIQUE above all other Bankais. So far, all Bankai's we've seen are HUMUNGOUS representations of their true forms, what with Mayuri with that Baby Poison Spouting Caterpillar, Komamura's huge Samurai Giant, Tosen's HUGE BLIND SPACE, Renji's Gigantic Snake Sword, and of course, Byakuya's extra hundred blades that become even many more thousand of petals.

Ichigo finally dispenses with the flashy displays and moves. His power is not flaunted or showed in everyone's face but rests condensed in a simple form. Remember, that the strongest dog never barks. Byakuya's reaction is not unique. If I didn't know what his bankai would really do, I also would think that Ichigo is pulling a huge prank.

Until one discovers that now to Ichigo, everything moves at tortoise speed.

One word abot Ichigo's bankai.......


EFFICIENCY

All the power that could have been manifested into a giant monster rests in a little katana. And what is the output of that Katana?

SPEED

Simple, yet elegant. Isn't that something we haven't been getting for some time? Its so refreshing to see a simple powerful move rather than something that takes an entire episode to recite the incantation.

The one thing we don't know yet is how sharp Zangetsu in Bankai form is. Of course it can cut through flesh, even a Captain's flesh. But what else can it do? I guess we'll find out next episode. Because Byakuya it seems, still has a trump card up his sleeve. So Ichigo better have one as well.


Oh, and as for why Ichigo didn't kill Byakuya, well, that's because the objective is to DEFEAT Byakuya and all the jerks who tried to execute Rukia. Besides, Ichigo knows that despite everything, Rukia still regards Byakuya as her brother. And Ichigo, being the sensitive touch nut that he is, knows it.

Plus the fact that Ichigo is a gentleman, unlike Byakuya who is a jerk. Nobility my ass.