I might give away my age and proclivities with this, but I wonder if any of the bakers are familiar with an older sequencer called Bars&Pipes which lived on the Amiga.
Granted, this was written before anyone dared to dream of audio in the computer (although I did have a decent audio card that let me sync my MIDI to audio, eventually), so the programmers had quite a bit of freedom that is only a memory today.
Anyway, the basic architecture was inputs, outputs, pipelines, and processors. Processors could exist anywhere, and some of the more interesting processors allowed one to send data to multiple pipelines. All processing could be destructive (between input and pipeline) or non-destructive (between pipeline and output).
It probably sounds simplistic, but it wasn't. You could do some really amazing tricks!
All that said because I've often wondered if it would be possible for Cakewalk to implement something similar for MIDI in Sonar. When the patch points appeared I thought about asking for something similar for MIDI, just didn't get there yet<G>! And the HUB idea above sounds like an even more interesting/flexible implementation of the idea.
So yeah... one more "AYE" for MIDI Patchpoints in one form or another!