Well the Kyuubi is bigger than an entire ninja village, even bigger than Gamabunta, so "mini" could be all realative.

i also like the 4th tail desgn, it looks really, I dunno, evil. And judging by what Orochimaru said, I'm expecting a big power jump.

I also thought it was cool that, the water in that tunnel place was only puddle deep before, but now it is really deep. i wonder what it signifys?