There is a request for channel grouping already (on the forums, I think), but so far this has not been implemented since it would require quite some modifications. You have probably already discovered the Store and Restore buttons in the Channel Manager which help at least a little bit, but that's of course just one preset and it's not stored across sessions.
While implementing support for more presets would take a while, I think we could improve the current behaviour when dragging the mouse over the buttons by not inverting the button state basically everytime the mouse is moved. That way, you could easily just move the mouse once e.g. through channels 1-20 and change all their states at once.

Ahh, nice, that sounds like a plan, Saga!

For the time being, we could indeed solve it like that, thanks. Any possibility and workarounds for easing up constant channel on/off clicking on my side would really take away much sweat and save time here.

Plus, when I'm too hasty, I often accidentally switch channels (drag'n'dropping / swapping two channels, although I only wanted to quickly set them off or on).

Please keep me updated on this!

r7086 (soon available from https://buildbot.openmpt.org/) contains the improvements discussed in the first comment.

Cool stuff. Looking forward for several-presets-implementation in some time then.

(i.e. what I meant was, you said support for more presets will take a while, can't wait for that, as well.) :)

Don't get your hopes too high though. The channel manager code is extremely unpleasant to work with, and I'd rather steer some energy into features that don't end in frustration on my side.

Yes, I would wish that feature outside the channel manager anyway (as I don't use it usually at all). Don't know if that makes it easier to implement for you though, to add channel grouping/presets directly in the pattern editor.