Regarding the support of midi CC subtracks, you’re certainly not the first to make this request, and I certainly see your point, from a usage point of view. Conceptually, a track that records notes as well as a number of different CC messages is easy to grasp.
BUT… (and this is my personal opinion, not genoQs’), I think the subtrack concept makes the machine too complex, UI wise. It’s yet another zoom level added, and I’m not sure if I’m waiting for that.
And then there’s the issue of memory. Adding 10 more CC values, or even worse, 10 NRPN messages to each step needs a ton of memory. And while it may be available atm, we could also use that memory for other features, logic, other data structures, etc.
So I’m not convinced yet, and for the moment prefer to use a number of dedicated tracks in the page for CCs. This also adds to the fun that certain CC tracks can have different speeds, lengths and plackback algos. Way more fun!