Can I change the question up a bit? What about what you'd like to see on the software side?
Improved Camera Software
Touch Screen to Wake
Flash (of course)
Better Media Player
Ability to remove items from the launcher or rearrange it
I'd love to hide Apps in the launcher, but in reality i'd rather just want to remove Apps like Amazon MP3.
Camera- i think the droid just needs a better lens, if you've got a bunch of pixels behind an average lens, you'll only get a very pixel-ed, average picture. But more time spent on the software would also be great, we've seen what apple was able to do with their simple 3.2 camera
Media Player- I'm actually satisfied, it does everything i need. it could be more visually appealing, but that's no biggy. I'd love to have an integrated
(GMote) style data stream over Wifi. If you could watch movies on your phone from your Laptop hard-drive without killing your battery.
As for UI, Does Sense take anything away from the Google experience? If not then i'd just rather Google purchase the rights to Sense and make that the core OS, then if Other Android manufacturers (Moto) wanted to release a UI replacement Google could just release the steps on removing the aesthetics of Sense so MotoBlur would still be the same and not need to be totally reworked.
I wonder what HTC would do in that case? What else could they do to a phone to make an HTC device more appealing than a standard Google device?