I'm a few modules away from a new milestone in a completed 4 row 84 hp case. In the top hole I want a XAOC Odessa once it's released. Maybe an ES-8 on the left. But I wanted to get your opinions on what, if anything I might be missing. I like doing mostly bass/sound design (lazers especially), simple techno beats, and some light melodic stuff. In the sketches the bottom rows were filled mostly with more VCAs and Filters. If you have any ideas or input I'd love some feedback. Thank you.

ModularGrid Rack

Put a few VCAs back in. Right now, you have sort of 4 1/2-ish, and while these deal with the audio aspects nicely, you have no VCAs for dealing with modulation and/or CVs.

Lose the '07 Mult. If the O&C's quantizing is driving the VCOs across all four channels, you don't have enough modules on each channel to require the buffering.

The flow on this build is sort of odd, actually...there's things up near the VCOs that would probably work better by the mixer, and vice-versa. For example, the Mir...it seems like it would be optimal for controlling and summing levels from your four VCOs, but it's not located in a row that's convenient to the VCOs themselves. Whenever possible, try and keep your patchcord lengths short as longer ones can pick up electronic crud more easily.

As for filters...you might look at G-Storm's stuff, most notably his ARP 2600 4012 VCF clone. G-Storm's VCFs also usually have the convenience of dual input mixing...very convenient!