I've replace the original rack with a new setup. I tried to make it less cramped.
I replaced several modules starting with the oscillator and replaced it with an Instruo Cs-L. In my main rack I stayed away from complex oscillators since I wanted the functions as discrete modules so that I had more control, but in this case it's nice to have a lot of tools in a somewhat more compact space.
I still have 6hp to fill, but can't decide what to put there. If I go with this setup, I may just leave that blank until I have a better idea of what I need after I've played with it for a while.