First: I want to see live MIDI as well as audio in the system. Your picture shows Audio In, Audio Out and MIDI Outs; I cannot understand why it couldn't include MIDI In.
Second: I agree with keeping sequenced parts on the composer window. However, a label on the patchwork with the partname connecting to its target might be extremely useful, particularly if it copied the part's colour.
Third: I tend to agree with DaveL on the racks - I think it's worth having a "basic mixing desk" and "modular mixing desk" with a "make musession modular" option (but no way back). If it were me, I'd be looking to make the "rack" desk just a constrained version of the modular desk - i.e. pre-wired with assistance for plugging stuff in. Don't try to present it as behaving "differently" from the modular desk.

