I'm not really sure about adding them. Although I understand why they could be added, they feel a lot more like segment RTAs which generally don't have any official leaderboards. The boss stars basically act like keys do in Vanilla, so adding worlds would feel like having RTAs for lobby, basement and upstairs in SM64 because those are also areas and need a key for further progress to be made. Just that in SM64 you have three of these areas whereas this hack has eight. And besides being on the same overworld, these levels have a rather loose connection and except for the toad house stars, there's basically nothing that truly bonds them together. Additionally, like you briefly indicated by suggesting 4 categories for each world, I do think it would become a very wide block of categories, because those 4 categories per world are more of a minimum that we would end up with.

Either way, I understand the suggestion but it seems rather unfitting given how hack leaderboards are generally structured and given that the levels are largely seperate from each other, while mostly forming not much more than key areas of the game but nothing that could truly fit the category of a "stage RTA" in the broadest sense.