1. So you're for lowering the skill ceiling. I'm pretty sure every competitive player can agree this is a bad thing.
2. Literally all it does is pair you up against higher-skilled players.
Let me put it like this. I still don't think you get what I'm saying.
A: Why do you want to only face people worse than you 99% of the time?
B: Why do you want casuals to get obliterated by you whenever you play?
1: I'm for evening out the grand canyon sized gulf that a lot of AT's forcefully wedged into Melee's system, not for lowering the skill ceiling to the point where it's not competitive at all, which is the statement you seem to be trying to shove into my mouth.
2: And if the difference between highly skilled players and players that have a decent modicum of skill, but aren't QUITE at that level of elitism yet, is literally a huge leap, then being forcefully shoved into higher ranks after being used to people of your own skill level for so long, due to an auto-raising rank system based off of wins and losses, would only throw players who were not super competitive into a lions den, where they'd be continually slaughtered unless they were given the choice of going back to the lower ranks.
It would only take a lucky streak of wins against entirely new players to increase that score well beyond the point where it actually reflects their own skill level.
And if you enable THAT option of going back to the non-competitive side of the ranks, that gives leeway for the less savory members of the competitive community to go down into the lower ranks and start trolling the newbie players.
Auto-Ranking for this game doesn't work well.
Highly technical AT's would be the catalyst for forming that gulf, in Smash's case, hence it's better that the worse offenders of that group of AT's were taken out in favor of something more balanced.
As for A and B....
A: Why would you want to leave a wide gulf between player bases, especially if there's the possibility of elites being willingly able to skip between the two different sides of the gulf of ranks?
B: The same question you posed; Why do you want casuals to get obliterated by you whenever you play? Is winning so important that you'd support people who would jump into public matches and do that despite their level of skill?
Because that's what leaving the most advanced AT's in and segregating the population without strict restrictions on which side of the rankings you can play against would leave the game open to.