Most, if not all, of the accordion players I sold a Tyros/PSR to, were totally satisfied having 61 keys.
  Plenty of room for melody.
  The synth players were the same.
 Piano players wanted more, but grumbled about semi-weighted keys feeling unnatural for piano pieces.
  I guess, for the latter, it is a compromise no matter how you look at it...just what kind of compromise would be best.
  Ian
_________________________
Yamaha Tyros4, Yamaha MS-60S Powered Monitors(2), Yamaha CS-01, Yamaha TQ-5, Yamaha PSR-S775.