I assume by keyword collections you are referring to smart collections. The reason I choose range over selection is so I don’t accidentally select clips above or below what I want to select, just a personal choice.
I do with you agree with the generic video role being assigned to graphics. Same goes for still images. Nothing wrong doing it manually just not very darn efficient. Looks like Final Cut is not always intelligent when assigning audio roles, something I always double check. How can foot steps sound like someone talking? I guess one too many beers or other sauced up beverage of choice at the bar can result in that scenario.
One other thing that bothers me is no choice in assigning a transition to video or audio only without expanding the two. Then using a transition out Motion for audio only is not great either. You choose to add a video transition of another kind and it changes the duration of the audio transition as well.
For all the great things that Final Cut does well there are those things that kind of piss me off. Still with all of its shortcomings I still like the software.