I never used a word remotely similar to TELLING... I said (and believe) that you shouldn't even be SUGGESTING the use of Onett... If you're trying to level the playing field then use stages that don't favor a lot of characters so much... We had a big discussion in one of the NEOH threads about why Japes and DP shouldn't be legal stages...
If I could snap my fingers and make something come true, I'd make a ton of custom stages, one per character, and each one gave an individual character a slight advantage while helping no other. Then we'd have starters and all the CPs.
Unfortunately, it isn't that clear cut.
History has shown that you can't balance smash for single character users. When you do, you do so at the detriment of anyone who wants to have a secondary. The best characters end up being those that do the best on the most common stages (starters), and all CPs become weak and frail.
When you recognize stages that aren't necessarily good for certain characters as legitimate until proven to be detrimental to competitive play (imo, stages that lead to an auto-win for a character regardless of matchup, stages that result in consistent and uncontrollable stage intereference, stages that result in consistent and uncontrollable low % KOs, etc.), you are allowing other characters and playstyles to be available.
To "level the playing field" with only changing stages, we can't hurt any other character arbitrarily. I have yet to see a reason for Onett to be removed, so I put it on. I've played on it a lot and have found it to be a good CP for characters like Olimar, Lucario, Fox, and D3 if his opponent is CGable and doesn't have a good projectile, but not broken for any of the characters in question. Removing the stage merely because it is different or because we find that several top tier characters that do excellently on standard starter stages do poorly here is an unacceptable arbitrary change.
If you ever think a stage is super broken for some reason, just read the initial post and follow the process. ANYONE that participates in the circuit can get a stage banned, for good, in the MWC. If it's banned in the MWC, you're probably not going to find it elsewhere. If you reeeeeeally hate Onett, make a few vids, maybe throw on some commentary, or just abuse it in tournament. People used to be scared about the D3 infinite without cause and many regions banned it solely because of that. It is entirely possible that characters like Olimar or Fox could have been much more widespread without the banning of this stage. D3s would have taken people there all day, people would have countered by picking non-CGable characters that do well there like Pikachu, Olimar, Fox, etc., or by characters with their own infinites like Diddy. Removing a single stage changes the path of the game towards something that we've created rather than what the
game creates.
My process is slow, but any broken stages will be removed and any non-broken stages will stay. It's the best way to get the perfect ruleset over a course of time without inadvertantly altering a game's metagame.