The problem is not so much the sounds on your keyboard, it's the keys themselves only having 2 elements that control the sound.

Set velocity per note pressed and mono variable after touch per note pressed is by no means even remotely close to what is needed to reproduce the expressiveness of a real-world instrument.

For that we have devices like the WX-5 and EWI which do a fantastic job and when used with the right sound source, they can be just as expressive as the real-instrument themselves.

Connect a WX-5 to a PC running WIVI and you have nothing short of digital perfection. Heck, even WIVI running off a breath controller connected to a keyboard would blow your mind.

Regards
James