I'm sure I'll catch some heat for this but the core of my arguments against said rules is for imbalance.
By promoting stages certain stages, banning others, banning items and counting percentages as hit points you've effectively banned over half the characters. Who is going to fly further? Pikachu at 28% or Bowser at 29%? If Yoshi 64 is in play and Fox gives the run around, with items on isn't there a fair chance someone could get a ray gun, a heart, food, etc. to break the cycle? Don't characters such as Fox have a large advantage over most characters on Final Destination? I think you see what I'm getting at.
As for the "Tournament rules don't affect casual play" argument, it's even clear in this thread how casual players are frowned upon and served derogatory statements such as "scrub" (spare me, I was around when that phrase was coined) I'm not saying you shouldn't play the way you want-- quite the opposite. I am however saying that tournament rules do not lead to a true test of skill, are not "balanced and fair", and probably cannot be. Perhaps they are the best you've got and can come up with but I still find it severely flawed at best.
/my 2 cents