Resurrecting this old thread, found it very interesting.
I'm struggling with this a bit at the moment as I embark on expanding my system a bit. I haven't taken that much of a deliberate approach to designing my system, it's been much more about getting things that seem interesting/inspiring. And to some of the earlier comments, it definitely feels like a kitchen-sink situation at the moment.
However, when I get the urge to consolidate and focus, there's nothing I really want to get rid of. Do I use all this stuff in every patch/song? No. But I do find it fun and inspiring to have all the alternatives and options ready at hand so that the next patch/song can do different things.
Including utilities, (too many) sequencers, and in-case mixer I'm getting close to 24u/104hp in two suitcase style cases. It still feels quite portable, but each case is not stand alone. One is all generator and modulation, the other is all sequencing and control. I've been fairly happy with this, but I do like the idea, conceptually anyway, of self sufficient cases... or even self sufficient half-cases (6u/104).
Maybe alternating rows of "voices" with rows of controllers? That could be interesting.
Although, to be honest, I don't really know what problem I'm trying to solve right now anyway