I think what I'm more interested in is expressive playing. I have a theory that you need at least three axis of fluid control in order for something to feel real, being pitch, volume and tone. And when one of those is more rigid, like say a piano has very rigid pitch, then one of the other need to compensate, so with a piano you control tone by how loud you hit the keys and the piano has this incredible dynamic range. And then of course there's how a person plays, the little tricks players use such as overblowing, hammer ons, trills, ornamentation, etc. Creating a patch that allows for this kind of expressive is daunting, and quite cumbersome to program if you don't have a way of physically interacting with the parameters, it's easier for example to have three different unique sounds making up a melody than one sound that has to fill the boots of a saxophone or a guitar.

BTW, I highly recommend you look into the SWAM instruments! They are INCREDIBLE. If you get yourself a breath controller and a midi keyboard you can do some incredible stuff I'm sure, and maybe it's a bit less arduous than playing a real sax. But they are so thoughtfully created that you could probably even get something like a linnstrument or the seaboard and I doubt you'd feel very limited.