While discussing different strategies in the modern speedrunning discord, I realized that there are no leaderboards for individual level runs in this game (or sticker star for that matter).
Personally, I think this would be a fun idea barring perhaps a couple of paint stars that essentially require the player to do the same thing as another paint star (i.e. Kiwano Temple and Mossrock Theater), as they are much shorter in length compared to the other categories and runners could reset after completing runs to have a save ready to try again if desired, rather than needing to start the game over to get to that point.
Details such as colorless spots, cards and other such collectibles should be discussed of course, what do you think? I personally would be down to select a particular paint star as a trial for a bunch of people including myself to run, see if this IL has merit and then go from there.