Not knowing the M32 I'm not sure what it has and what it lacks, so I will just make some minor suggestions for improving this rack.
I think something like the ALM O/A/x2 is a better use of 4hp than three passive attenuators. You only get two channels but attenuvert and offset is more useful than just attenuate. Alternatively you could get a 2hp dual attenuverter and a 2hp ADSR in that space, and replace the (large) Doepfer ADSR.
Considering you already have Maths in there, it seems quite wasteful to give up so much space to another envelope generator. There are a lot of smaller options if you really want an ADSR. Mutable Instruments Peaks (or one of its smaller clones) could do this job while also giving a lot of additional possibilities.
There are a lot of modulation destinations in here but not so many modulation sources. Is the M32 + Maths enough to drive all of this? You probably want a CV mixer of some kind too.
The Quad VCA seems like a solid choice, but personally I would go for the new Veils instead.
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