[crazygringo]

> There is no technical or physical limitation that requires semi-weighted keyboards to have less expressive range.

Of course there is -- it's not a technical limitation of the instrument, but of our physiology.

If there's more weight resisting, this gives us a wider range of control, for the reasons I explained. Of course only to a point -- once it gets too heavy that a light touch can't move it, or the heaviest touch becomes too fatiguing, you've gone too far. But pianos are weighted in a way that approximately maximizes our level of expressive control without being fatiguing.

So yes, semi-weighted keyboards inherently have less expressive range. I mean sure, not if you're a robot playing with infinitely fine motor control. But for actual human beings, semi-weighted are absolutely less expressive. There's no getting around it.

And with regards to the one extremely light-touch piano you found a joy to play on -- I'm quite sure that it couldn't have been played extremely softly in an even way. That's just the inherent tradeoff. If you're playing music than never goes to ppp then maybe you didn't notice. But I don't need to see the piano myself -- this is all just physics and physiology. It's inherent to how it works.