What about the following behaviour: When the regex is matched, the first extension using this regex is highlighted on the PopClip bar (and thus can be executed faster by pressing return).
I’m hoping for this soon as well. Half the battle is having too many wonderful extensions but not needing all of them at any given moment.
Maybe an option to rank extensions based on match as well. #1 would be the first extension that shows with the next extension being #2 for any matches to selected text.