I would be interested to see how optimized we could get individual track times. I have always loved this game and I personally have always wondered what the fastest time was for each track. Although yes it would be a lot of work to verify and set up but you could even split it into 2 sub categories(all out and no nitro). Racing games are often competitions to see who is the fastest. Often times you can have racers who specialize in certain tracks. For example on Forza Motorsport, in my network of friends, there are sum that are really good at long tracks like Nurburgring and Le mans but they are terrible at smaller tracks, and vise versa. I think it could bring a breath of fresh air to this game and its speedrunning community.
What if there was a category for a restoration lap time. Where you have to get a vehicle from the junk yard, fully restore it, then have to set a lap time with that vehicle. All in one run. It would add some luck to a run, plus see how well you have mastered repairs.
What if we had another set of leader boards for all the categories but you're not allowed to have the keflings farm or transport resources. We could call it lazy kefling runs. Any thoughts? The idea for this came from my brother you never makes the keflings work.