I really like your stack mockups for mixers, but all plugins in a single window could become unmanageable quickly.
If i think about it, a double height insert would make sense.
I.e.:
First slot would act as a plugin:
- Clicking center of a stack would open smart-control view of the stack (like it opens a plugin window)
- click left side would bypass all plugins
- clicking right side would open a plugin menu
Second slot would be the arrow, that expands the stack so you can see what's inside, and can open separate plugs inside the stack.
To adjust the macros you would have a small (i) on top of the smart controls window (like now) which would allow you to assign the knobs, the stack would auto-expand if you hit the "(i)" so you could assign parameters by learning?
RE: management of plugin windows, instead of having all plugins in a single window you could have "expanded view" of the smart controls handled like having smart controls at the bottom, and selected "plugin GUI" at the top.