title says it all … works on audio, midi, group tracks but not on Inputs and Outputs which is a pitty …
bug, feature or scheduled for the next update ?
Probably a bug (oversight), which Steinberg would call a feature of the new mix console, and will surely be updated to work in the next update.
Having images on the input channels make a lot of sense
colors would be cool too 
Right. This is something I noticed the day I got C7.0.0. It’s been touched on in the Issues forum, so maybe it will be addressed in a not-too-distant point-update.