This is in a way building on 4d9r's thread, but I wanted to share some of my ideas.
Quests
First of all, for the quest leaderboards, we can have 5, 10, 25, 50, and all quests for the classic, crossroads, and fall map, which seems to be coming to portals soon. I still think there should be no perk and perk versions for all of these categories.
Races
Next for the race, split it up into the winter, crossroads, and classic map, and I also think there should be a no perk category for all of the races, alike the quests. To time the race, the best method is slowing down a recording and finding the last frame the mid-race timer is open, as the endgame timer is broken and shows the incorrect time, sometimes even showing negative numbers.
These changes would add more clarity to the Marble Mania speedrun leaderboards, as right now, there is some chaos, having some runs in wrong places and categories crossing over.