[this part edited out because I cluelessness missed the single segment any% category already existed] Proposition for a 100% speedrun rule:

Play the game to get to Mac's Last Stand and win 10 times to unlock Champion's Mode in the exhibition menu, accomplish all of the Exhibition challenges and beat all of the boxers in champion mode too. Get back to Last stand and get defeated 3 times to get to the credits and it's when the run ends.

[more uniformed non-sense edited out from my part] Seeing that only IGT (In Game Time) is counted, I would suggest, as it is already the case with the any% run, to not count the time between fights for menu navigation.

Any% for PO Wii is already a thing. You can find "Full-game Leaderboard" in the menu to the left. Basically you beat all fights and lose three times at the end.

100% would probably include all the medals, as well as becoming the champion.

Oh, my bad. So, Any% include losing as fast as possible in Mac's last stand to get to the credits? Allright. I still feel like you should actually beat Donkey Kong to consider it complete, but I can see the idea.

So, for a 100% run, should the rule be to once you get the 10 wins in Mac's last stand to unlock champion mode, be to go in the exhibition mode to get all the medals and beat them in champion mode, then come back in career mode and lose as fast as possible so you get the credits anyway?

I actually don't know how you get consensus in rules, for speed runs.

Well, 100% would indeed include getting all the medals from a fresh file. Although I don't know how we would end it. Maybe Zallard1 would like to bring us his opinion on this?