I tried some feature in Bitwig which I would consider useful also for Ardour:
When operating a hardware controller a small overlay message pops up showing parameter and value changed.
This is very helpful as it allows to see the immediate feedback on the screen to the recent actions.
Feature requests belong at http://tracker.ardour.org/
Posting them here tends to guarantee they will be forgotten, regardless of how good they might be.
In this particular case, this might work for a small controller where you typically only use one physical interface at a time, but it will not scale to large scale control surfaces. Consider what happens if you use 8 faders at once ....