I get that a lot of people feel no LTE is a deal breaker, but I live in the U.S. and don't need LTE, I don't own this phone (yet) but I would love to. If removing LTE means lower cost and more "open" then I'm 100% all for it. Besides, HSDPA+ is plenty fast for some. +RE Ausetkmt
As for why it's only offered on T-Mobile, I don't think that's up to Google actually. Typically a manufacturer (in this case Google, though LG makes it) shops the phone around, a carrier usually has some demands and they come to an agreement. I would not be surprised if AT&T did not want a Nexus device given that Nexus devices let you sideload, tether and video chat without any carrier lockdown.