PSR2000/PSR2100 is ALMOST an ideal keyboard. It just lacks the following:

-The default registration should revert to the last setting !
-Vocal harmonizer can be improved, not sure how since I am not an expert. But I don't sound like a choir when I sing thru it no matter what adjustment. It still sounds weird and robotic. Make it simple but sound like a choir right out the box. The mic settings is great though. It will be great if you can save the VH and mic settings as part of the registration
-Also, maintain the voices categories in a registration memory. For example, for the RH voice keep the piano settings at grand piano, brass at pop brass, strings at slow strings, etc for a given registration setting. So when I press that registration button and press the piano button I know I am going to get grand and when I press the brass I know I will get pop brass, etc.
-Recording: should have an easy record function like some of the low end psr line of the past. Just press record and record away all the tracks (RH, LH and rythms) and press stop to stop. PSR2000 is a bit more complex.

-Han