What I would be looking for in a ROM:
1. No bloatware, AT ALL. DSPmanager would be okay, but nothing else (not Beats audio for example).
2. As close to the stock android experience as possible. I run CM10.2 by cofface right now and that is spot on. Good performance, battery life and pretty much a google-only experience and everything looks stock. I don't want my phone to look like a thing that has been "hacked" by a kid to make it look ridiculous - if you know what I mean.
3. Kitkat (4.4) would be mandatory. There is no point in developing a ROM for 4.3 since there are already great roms for that, and nobody wants an outdated version of android on his phone right?
4. Root. Pretty self-explanatory.
5. Installable via CWM recovery. The 4.4 roms that are available right now can only be installed via some weird custom recovery afaik. I really don't want another recovery on my phone.
6. Great performance without affecting battery life.
7. Lockscreen like CM10.2. Cyanogenmod has a lockscreen clock called cLock, which is the best out there. This would be awesome to have.