It would have less to do with hardware and more to do with the strategy behind it.
To put it bluntly, the Nexus One has been a failure. The entire retail philosophy behind it has come crashing down, and taken the reasoning behind its existence with it. Even more, the death of the CDMA Nexus One has completely undermined the carrier-independent mission of the sales model. (choose your phone first, then choose your carrier) With the Nexus One switching to brick and mortar sales, Google has no incentive to make a Nexus Two.
(And I would wager quite a few of Google's manufacturing partners were miffed at the way the company handled the entire thing, and the switch to a regular retail model will only reinforce that anger and frustration. )