Upgrading to a 6u case and figuring what else I can add? I’m thinking a MIDI/CV module for sequencing externally and maybe FX?
I'd definitely start with more audio sources. Maybe a Plaits or two to pair with the Braids. An output module would be nice, and if you're thinking about adding FX, check out Happy Nerding for a great output stage that also contains a second stereo input with attenuator, which is super-handy for adding reverb, delays, etc to your stereo mix when you don't have a mixer with an AUX send/return.
MIDI/CV...IMHO, Expert Sleepers for the win there. You'll just have to sort out whether you want to use just MIDI or if addressing the modular with CV/gate/trig under control via Silent Way sounds right for you.
Other stuff...hm...better mixing would be nice. The 2hp MIX is a nice summer for somewhere within a patch, but nothing beats a dedicated stereo mixer with panning and all that stuff. Plus, finding one with an AUX bus would really make the best use of the limited space open for a decent FX module. A couple more EGs and VCAs, and that'd sort of nail it.