Hello @liquidcolor,
Since you are looking to hear thoughts on the build, I'll share with you the two things that stood out to me the most:
I see 11 dual passive multiple modules between the two cases (if I'm counting correctly). That's 22 1-to-3 passive multiples! To me, that seems quite excessive, especially considering that Tiptop Audio stackable cables exist. Personally, I rarely split an output signal to more than two inputs, so I'm essentially replacing one of the 1-to-3 multiples and three normal cables with a single normal cable and one stackable cable. (But I've also never used a rack this big.) It also avoids having large clusters of cables at the multiples and additionally having to route the signal to and from the multiple, which may or may not be near the relevant output and inputs. Overall, using splitting cables saves rack space and money, even if you do have to use a second normal or stackable cable to split to a third input (remember that you can split the signal out of each end of the stackable). But like @farkas mentions, do what works for you. You may have specific plans or needs for your rack that I or others may not understand.
In my view, there is a shortage of sub-mixers and attenuators between the two cases. For example, where are you mixing the outputs of all of your oscillators and other sound sources? I see two Mixups and one Triplatt for sub-mixers. (The two VCA modules also mix, but I would think you'd mostly want to use those for other purposes?) In a smaller case, this would be plenty, but in a rack this size, and considering how many sound sources and filters you have, I would want more mixing power. Dedicated attenuators are also a really big deal to me. In your rack I only see the single Triplatt for this. How are you attenuating the signals going into the CV inputs of the 8-channel Doepfer VCA module and other inputs that don't have dedicated attenuators built in? Some of this may be solved by how you intend to use the Doepfer VCAs in conjunction with the Michigan Synth Works Fader Bank.
My solution: replace nine of the passive mult modules (18 HP total) with three Triplatt and/or Happy Nerding's 3x MIA modules. These are both endlessly useful modules that will give you both more sub-mixing and attenuation capability.
I hope some of that helps in some way!
Chace