I have one major feature suggestion and a major enhancement:
Major Feature: make it truly modular system. Make it so that modules can be placed arbitrarily in a growable rack. Have a library of modules to choose from and put in as few or as many as you need for a given patch.
Major Enhancement: Make the UI elements larger. The UI is simply too dang small. The knobs are hard to see properly and the numbers are so tiny, I have to zoom in my screen to read them easily. Perhaps each module can magnify when you are working with it and/or you can zoom in and out of the UI - magnify it to easier see the part you are working with and zoom back when you are done. To try and make the dot on the knobs a little more visible, I went in and changed the dot from white to red on every frame of almost every knob before I got burnt out on it.
Also, a major update to the TAE for a more accurate simulation of the analog circuitry.