I am new to AP (day 2 of the trail version) and I like it a lot. English is not my native language, so some things I have to learn.
But indeed the use of color channels is not easy. I use my older Photoshop till now (pre Adobe Cloud) for mainly astrophotography.
So I work also with gray scale images I paste into the RGB channels, especially narrowband. Just simple work, nothing complicated.
But now with AP I can not manage to do that. The videos here and other topics I found do have some work arounds but I don't understand those.
So yes, if a more intuitive way can be made to simply paste into and alter color channels, that would be a huge step forwards