Yes and for the reason I explained it doesn't need to be visible all the time. LFO's, FX, MSEG aren't visible all the time depending on which Tab has focus.
So what is your plan to display
all the faders from each layer at one time without making the main GUI cramped ?
Your mockup above only shows Osc 3 and of course you realize it's tabbed as well.
So the options are: Make the GUI bigger. People will complain. Add more Tabs. People will complain. Cram the GUI to the point it looks like PolyAna. People will complain.
It breaks down to mouse clicks and cursor travel. How many mouse clicks and how much cursor travel does a new feature eliminate ? In the end is there really that much time saved ? That's the question.
The only way to know is to test each concept and find out which one is most beneficial but in the end once again it won't add to or change the sound of Dune 3 one bit.
Good luck I hope you get your wish. It doesn't look like the LM is a high priority but you never know what Synapse will do next.
I've already done over 50 patches for this latest D3 update so work flow is really a non-issue here. A Layer Mixer would be nice but not a necessity or top priority here.