AES design questions

[David Honig]

1. Why does AES require 128 bit blocks?  Any other reason
than to make ECB codebook attacks tougher?

2. Why does AES require >128 bit keylength support?  2^128
is not practically breakable.  What am I missing?  Is this
simple "overengineering" aka "safety margins" (plus "bits are cheap, but
not so cheap that using minimal-128 isn't worth it
sometimes")?