I understand the idea, but it doesn't make THAT much sense to me. If it should be implemented, 'recent' should mean maybe 3 in the list max!.... Like when you are working on a group of tracks that all need similar polishing; and the last used fx are there. A 'recent' list showing the plugins I GENERALLY use most won't really work:
...most people will always have the same 'recent plugins' showing up in the list...(so why not make a favourites folder in the plugin layouts).....and if they ever do add an odd one in then the preferred list will be mixed-up again.
MAYBE: it should not be 'recent', but 'most used' list! showing the plugs most used in say last hours/days/weeks.
... at least this is what came to mind right now reading the post.