I can give a few reasons:
- The populus doesn't want it. Check this topic's
poll. It's a slightly different subject, but people only want one time period to be tracked. Also, Good/Bad Future are kinda the same sometimes and not others.
- If you use Stage Select, Time Warping resets your game. Accidents with Warps happen often.
- It'd be hard to verify valid and invalid stats.
- New competiton suggestions take AGES to go up. Just look at ks8's topic. As further proof, mike89 said it straight to my face when I asked him about Chaotix Special Stage divisions: "I would add it right now, but it's my duty as an Admin to be lazy and push that suggestion aside until I forget about it X)"
So, er, sorry. I'd've tried those brackets too.