Had a reply, MG ate it. Grr...
Logic 202 + Fractio: These are key to a lot of sequencing and timing trickery. For example, let's say you want something to appear in the mix every once in a while. Just feed the clock and the appropriate clock division to an AND gate, then you'll get a gate outputted from that that ONLY appears when both clocking signals are present. Another great use for the division is to slow down the sequencer it's next to so that you can sequence transpositions...or you can multiply the clock for TaDream-style ratcheting. That whole area is designed so that ALL of the sequencers...even external ones...can have their timing messed with really hard by everything from Boolean logic to random signals, and there's ample capacity for "abuse potential".
The Qx expander for the Quadrax is what's necessary to "chain" the Quadrax's EGs, with the potential of generating other complex modulation curves in a similar manner to the Maths. But you'll also notice that the Maths has capabilities to mess with the Quadrax via the Qx, and so on. Again, look at the modulation section as something which, if desired, can work as one HUGE mod generator with all sorts of possible outputs. And you can then avoid using the o&C for just LFOs by making use of the QPLFO and use some of the more twisty things the o&C is capable of...the unique stuff!
Varigate 8+: there's another purpose there, and that's its sequence memory. You can set up 99 different memories in the Varigate for it AND the Voltage Block. And having preset, ready-to-drop sequences that you can switch on the fly RULES. Plus, don't forget the timing section and how you can screw with these via that as well.
Bitbox: Keep it. You can use it to loop audio on the fly, play stored samples, and a bunch of other things. It's "stereo voice 5". Which brings up the voicing...
There are actually THREE voice sections on the top row. The first, optimized for pads, washes, atmospherics and the like in stereo consists of the Cs-L and Piston Honda, which sum in stereo via the Mixup. Then the second, intended for leads and the like, consists of the Belgrad and Sisters with the Veils being used for...well, a lot of trickery. For example, you could split the output of each of those VCOs to two VCAs...then take a couple of LFO signals to control them AFTER you've also split them and inverted one of each LFO split, with the result being stereo autopanning! Then, it's also possible to sum this AND the first "voice" via the Befaco for the Lester's inputs...or you can break out any of that and send it to the filters by the percussive setup. Then the THIRD voice is the Loqualis itself, which allows you to concentrate on specific results, such as bass. Also, there's a stereo VCA under it that can be used for stereo modulation of the Loqualis. But each subsection of the top row can ALSO be fed to the respective Performance Mixer strips, along with the stereo percussives. Hence the second Lester...it can either be used to process one of the above subsections along with the other one, or you can use it for stereo filtering for the percussives. And the Wasp and NE VCF are down there for alternate filtering...either on individual percussive outputs, or if you process the percussives via the Lester, this frees those two up for other duties. In short, you could configure this whole voice scheme whichever way you'd want, and in most every configuration, you've got sheer POWER.
Also, you'll notice that much of this build is designed FOR STEREO. You can stereoize most any of the above, in a huge variety of ways. Even the percussives have that Takaab stereo fixed-pan fixed-level mixer so that you can place the individual parts in the stereo field wherever you wish, and then either drop the output of that down to the Performance Mixer, or feed it to the Lester.
Similarly, the entirety of the modulation section is intended to work as something of a single "device", cued by the various gate/trigs from timing and sequencers, or from other modulation sources. You could even chain up the entire thing as a single, self-regulating and insanely-complex modulation source, given enough patchcords and madness. This then opens up the use of the modulation section as a "feedback" system, with everything intercontrolling everything else, which then gets fed back to other things. This is super-important if you ever opt to do generative work; as a generative mod source, that section is aces!
Now, the Tetrapad...it and its expander aren't on this because my idea would be to mount them...plus your matrix mixer...in a powered 4ms Pod of the right size. This would then be an expression controller par excellence...and since it's in a small pod cab, you can then position it anywhere you want, instead of having that stuck in the case. By putting these modules in a Pod, you're upping the ergonomic ease of use, basically turning the Pod into a super-overkill version of the usual mod/pitch wheels that can be placed by your keyboard controller, and connected to the main cab via whatever patchcables are needed for a specific patch. This would be just about perfect, and make it easier to make use of the Tetrapad and matrix mixer (which are great for modulation "global" changes...that's what my 3x3 Wonkystuff one is for, as it's intended for a fifth AE cab that'll house controllers and that system's Performance Mixer).
What I'd suggest is this: just STARE at the build for a while, with a pad and paper handy to make notes about patches, groupings, and the like. After several hours, you'll probably have a melted brain...but you'll ALSO have a clearer idea of what this thing is capable of. Also, keep in mind that, while this is one hellacious system, it's ALSO expansion-friendly. If you think about how the ARP 2500 was intended to be used, this would be the "Main" case...and later, you can add "wing cabs" to this and make things even wilder without needing to disrupt anything in this case. But also like the venerable 2500, you have your expression controls handy beside the keyboard controller. So, yeah...there's a half-century of ideas in this mo'fo!