I had to deal with the many channels/one track issue decades ago. Well, at least 18 years ago. The answer from MOTU at the time was "one track/one channel." I checked with them again about 9 years ago. Same story. I don't think it has changed, but I'd have to experiment with device groups and such before really confirming that. No, the method I use is multiple tracks, and it's not at all an editing nightmare. Very easy to select what you want and alter it either in the Tracks Overview Window or the multiple-track MIDI Edit Window. When you can see all MIDI tracks overlaid in the same window, they are very easy to edit. The most difficult part is selecting the controller data that goes with each track.
I have a shortcut for that which can be found near the bottom of page 2 of the DP Tips Sheet sticky thread in this forum.
Anyway, you just drag what you need to a separate track. The only thing that is at all tricky is to make sure that you leave controllers in the OFF position (value of 0) at the end of any block of MIDI data, so as not to keep playing, and with most VI's you probably don't even have to do that.
You say you want "features" and not "work arounds." DP is designed for customized workflows. One person's coolest feature may seem like a workaround to another, but that customizability is one of the reasons I love DP. The shortcut in the Tips Sheet may seem arkane to some, but for precisely the need that this user has proposed, that shortcut works wonders.
Most of my workflows have originated with a problem that I studied for a while, looking for a "feature" that solved the problem. In the process, I learned what the actual parameters were for each such problem, and then was able to take existing features and customizable commands (Commands Window: SHIFT-L) and string them together so that in a few keystrokes I had what I wanted. I've used the Search command extensively in this way, and I've used Custom Consoles extensively, too. But the Commands Window is the gold mine. That's where you find the commands not listed in the manual. Print it out and index it if you can.
Those index tabs are merely pieces of Post-It Notes that I've written on, cut out, and folded double to seal together and latch on both sides of the page. I know it is a lot of work, but it saves me a lot of time.
That's how I do things. Once you've created a workflow for your specific needs, that method seems very natural, even though it may be unique to you alone. DP is deep, but not difficult. It just takes time to find all the advanced features.
Still, multiple MIDI channels through one track... I don't think that's going to happen in DP.
Selection is the focus here. You've got to be able to select what you want and drag it quickly to other tracks in the Tracks Overview window. It's fast to create another track, even an identical one, data and all. You can use MIDI faders to bring them up or shut them off. With Custom Consoles, you can even group faders so that one works backward from the other, creating instant crossfades with a single stroke of a fader.
There's more, but I have to go now...
Shooshie