I'd really love the ability to load in sample WAV's into the elements to create our own drum kits then load them back into the T2 as TVN's. There are 10 user slots for creating your own kits by editing those already in the T2, but where as we can load in WAV's for creating new voices (up to 128 of them which I've done) you can't load these into make drum kits it even tells you this in the manual as Scott Yee and myself have found out.
Also 76 keys is a must. Forget the home users who are happy with 61 keys and put 76 notes on instead for all the pro gigging musicians. The home users will not mind since they will not be carrying it if it's stuck in their living room all the time.
Try to keep the weight the same by using different materials. Take a look at the Ketron SD1, that's 76 keys and light weight.
I'd also like to see the mod wheel and pitch bend reversed so the pitch bend is nearer to your left hand. For some reason manufacturers always seems to put the pitch bend wheel first then mod afterwards.
Maybe putting the mod and pitch bend wheels further up to where the power switch is and then moving the power button to somewhere else would make the keyboard the same size but still be able to get 76 keys on it? again as on the SD1