Penguins are cute
Your 3.4 suggestion is indeed somewhat of a loophole, we'll also probably discuss about it, but I can't really think of a realistic scenario where both teams suddenly at the same time don't have enough players to finish the match.
4.1 is already technically dealt with like your first proposition, as anyone using hacks in MKU is banned from mkc. Because it is a mkc decision and not a MKU one, it's not in the ruleset.
We already tested neutral starts in one of mkc Agility tournaments (I believe it was the 4th?). Overall feedback is that it didn't make that great of a difference, as with the 8 tracks pool, variety was enough for teams to find the "track pick advantage" by just getting a track they practiced more.
We also tested the track ban system in Agility 3, and once again, most people (to my knowledge) thought it was a fun gimmick but it shouldn't become a stable of the competition.
Lastly, as MK8d laptrolling is way less punishing for runners, and the teams that gave it a try didn't really meet that big of a success, we don't really think laptrolling is (on the current way of playing the game) breaking competition as a whole, and therefore should be banned
Thanks for the feedback.