Re: What do you want in Key Lime Pie?
Most of all, I want Google to focus on the battery life. I'd rather them take Apple's approach on notifications, pause apps, and only let certain services run in the background than what they're doing now.
I'd also like them to clean up the lockscreen a bit. The way they did widgets seems a bit tacky.
Full backups of wallpapers, ringtones, apps, app data, app placement on homescreen, etc. via the cloud.
Option to initiate voice as soon as you activate Google Now by swiping up from Home button instead of bringing up Google Now cards and having to either say "Google" or taping the microphone button.
Default video chat app like FaceTime but cross platform. Obviously if released on iOS, users would have to install it on their iDevices, but it should come default on Android devices.
Same thing for a messaging app. Get rid of G+ Messenger and Google Talk. Merge into one that integrates with the texting app. And integrate Google Voice too.
That's all I can think of for now.