Yes, I would get a much larger case to start with, perhaps a 9U Doepfer case? You also need more support modules: VCAs, attenuator, matrix mixer, and modulation sources like LFO and function generator. Also, I would get rid of the Rainmaker module way too large for a smaller setup. Replace it with something smaller like Erica Synths Pico DSP or Happy Nerding FX Aid.
Here is a suggestion on your build above to improve it:
I removed the massive Rainmaker and replaced it with Happy Nerding FX Aid unless you plan on larger case.
-Added LFO with 0chd
-Added function generator- Make Noise Function
-Added VCA- Tangle Quarter is great
-Pamela New Workout: great clock that gives you many other things like logic, Euclidian sequencer, and much more
- passive attenuator