My point is, the reason you don't have the stamina and strength to cope with even a semi weighted keybed is that your fingers are not conditioned to deal with the stress and weight of heavier keys on a synth...let alone on a real acoustic Piano. It's just a mechanical thing. You could be a VERY strong man with real strong hands and yet not have the finger strength to deal with heavier keybed. This has nothing to do with one's musicianship, other than the fact that when your finger don't do what you want them to do, you can't be as expressive and musical. Your fingers can't be flowy and all that.