I think the only banned stages should be:
75m
Bridge of Eldin
Flat Zone 2
Green Hill Zone
Hanenbow
Mario Bros.
Mario Circuit
Mushroomy Kingdom 1-1
Mushroomy Kingdom 1-2
New Pork City
Rumble Falls
Shadow Moses Island
Skyworld (I'm VERY MUCH on the fence about this)
Spear Pillar
Summit
Wario Ware Inc.
Big Blue (I'd love to test this more)
Corneria
Temple
Any liberals disagree?
I have a borderline-legal stance with Green Hill Zone (especially if Pirate Ship and Picto are considered legal). I'm not sure about Onett though because the walls do affect the matches significantly, even if the cars interrupt any infinites.
Big Blue is broken, I went vs. Meta-Knight (BPC) on that stage to test viability with him, and it only took him about three minutes to get onto a platform (and pretty much do nothing) I couldn't reach. (Because he guarded it until the platform I was on went out of range) I couldn't get to him again for over four minutes, and it was only with about 50 seconds left on the clock that I was able to do anything to him.
It can't really be called "stalling" either under the current definition (which doesn't include circle camping either), because he's technically getting himself into an advantageous, strategic position, rather than running away and abusing a character move like regular stalling.
Wario Ware is totally legit. Its a calculated risk picking that stage. Just like Pictochat. The hazards are harmless and the walkoff segments are temporary. Power ups aren't more powerful than the random things that might happen on other legal stages.
Scenario: Two characters both succeed in a mini-game
Result 1: One character gets nothing, the other one becomes big and has several 1HKO/2HKO moves now because of the small distance to the kill barriers. GG
Result 2: One character gets big, and the other gets a star. GG
Result 3: One character gets nothing, the oher gets a star. GG
It just doesn't work, the randomness is too broken. If the bonuses could be disabled completely, I'd consider it a counterpick at best, but that's not the case so we have to ban it due to 100% unfair advantages.
So if I have such stages as Norfair, Japes, Green Greens and Pictochat legal should I have no reason to ban PTAD?
Pretty much, the cars are not as much of a threat as people make them out to be (Most friendlies that I have against other players that are experienced with PTAD have little-to-no influence from the cars. Most of the time, the fight can go on just fine with them going underneath/to the side of us) If they don't like it, they can make it their personal ban, though it isn't that hard to learn, really.
Test I know what you are doing and I won't even fall for it.
I don't have YI:M legal. Should I ask my scene for their opinions about the stage or what?
The cars don't really kill at 40% unless you are Puff and if you DI.
I think you should, I haven't noticed any notably overwhelming tactics on the stage, and walkoffs aren't as hard to deal with. The only potential problem I really see on the stage is the insanely close left kill zone, which can result in <100% kills, but other than that, I see nothing different from the other counterpicks.
In Pictochat you MUST be awared not to be at certain places at certain moments, if you ended up there because your opponent sent you there, you were outplayed. Is that so hard to understand?
Except that the whole stage can be considered a series of "certain places", because, contrary to popular belief, there isn't any safe zone, not even off the stage (unless you count being under the right ledge). However, even with that, it's still more usable than WarioWare. In the former, the chances of the stage literally ruining the match are about 1/100 (which is still way higher than anything else legal when stage knowledge is anywhere near decent (Fixed-trajectory lava plumes are easy to avoid), but that's besides the point), on WarioWare, it's pretty easy to say that nearly every match is ruined by the bonuses.