Basically I'm saying that I bought a DMC-6 and making my own firmware for it. The Hagen won't suffer any modification like your solution, just a clever organization of the presets. It will also control my own gear like a Timeline. So basically it will be a better solution, at least for me
I'm not affiliated with Disaster Area Designs, they just gave me some programming tips, I'm making my own firmware for my own personal usage for my own personal gear.
Edit : more about how it'll work : I set up 16 presets on the Hagen with all the possible configurations of channels, loops, masters. On PC1 I have channel 1, no loop, master 1, then the same with channel 2, 3, 4, then I do the same with the loop on, and I redo all the stuff with master 2 on.
Then I can set up the DMC-6 with hard coded presets (like send PC 3 to Hagen and PC21 to Timeline on bank1/switch1), but I can also apply CC-Like controls on the Hagen like toggling the loop or the master applying a decay on the PC number to the Hagen.
You can see it has nothing in common with your idea. Once again it's made by me for me.