After recently acquiring a Faderport classic, I noticed that its implementation in Ableton lacks a few things.
1.) There is currently no way of accessing channels that are in a closed group. The Faderport simply skips the channels if the group is closed, and there is no shortcut for opening and closing groups. Going from the faderport to mouse or keyboard to open and close the groups is very counterintuitive to the intended workflow. I think adding the latter functionality, a button combo to open and close groups could easily solve this problem.
2.) SOmewhat related to the issue mentioned above, the faderport does not track the individual faders within a drum rack, regardless of it being a sliced sample or drums. There is only access to the BUS fader of all of the samples, and the left/right button will simply skip to the next group/channel and ignore all faders within a drum rack.