That'd be nice if it:
1) fixed the things they broke with 1.3.1 (system sounds and sprintnav audio, for example)
2) fixed whatever has the memory leak in luna that causes my phone to slow down over time, and eventually give me the 'too many cards open' error
3) gave us a version of google maps on par with what is on other platforms.
Those are the things that are in dire need of fixing, IMHO. Nothing new, just fixes. A couple of others that would be nice, but unlikely in that time frame:
1) fix the $#@! lag!
2) socket access. Come on, this is a COMMUNICATIONS device. Let me write code that can easily communicate over something other than http! Maybe some brilliant homebrew folks will create us a generic service that can be used this way? One can hope.