Potator definitely needs an update. I've found that no games retain the high scores on Potator when their cartridge counterparts do. Fast-forwarding would be a nice addon. I said pretty much everything before...
Netplay would be an interesting feature. Connect to WiFi, select which supervision game you want to play, and wait for someone else to join you. For games like kung-fu street, this would be perfect.
Also, overall, the sound (on the games that have it) could be improved a bit.