1. more consistent media playback. I love the ability to download alternate media players, but I think they need to make some work on the default media players as well. it doesn't have to be 3d or anything stupid, but built in id3 editor and some eyecandy would be nice
2. fix scrolling hangups. Recode the memory manager to give preference to UI elements so you don't get weird hangups. infact, optimize the memory manager completely.
3. Built in color customizer. Allow people to give the stock phone an orange, blue or pink feel. downloading custom roms is nice for this, but having a built in option would be amazing for those customers terrified of root.
4. Syncing/backup. Make a cloud based media manager (would be awesome to show off html5). It's also vital that they make factory resets/new devices
5. Google Documents support natively. allow editing and syncing out of the box. Also make wave native as well. Tight integration with google is a selling point, capitalize on it. While you're at it, fix the facebook app.
6. Clarify the Google Experience tag. Make it mean certain hardware specs, and make developers commit to upgrade path.
7. Push Gaming! This will be helped immensly with an android tablet/pmp. so do it
I love android, but some simple tweaks could make it blow others away.