Let's see, for me....
- multiplayer is not important, I want pick up and go. I usually don't have time to be searching for other players.
- since I know what type of graphics a PowerVR GPU can produce at 854x480, I want to see immersive graphics. And I don't expect to see slowdown.
- I am particularly fond of racing games, and certain arcade racers work well on a mobile platform. Nice tight accelerometer steering is a MUST, I don't want to be tapping onscreen buttons or using a D-pad
- I'd like to see some flight simulators like the X-plane series on iPhone, I know the latest wave of Android devices can run them.
- The ability to bond a bluetooth controller (Wii, PS3, etc) to the phone would be nice for gaming. Especially emulators.