I brought up Lando-i and Keldeo because they play the same role as Charizard Y. However, unlike Charizard Y, they don't need hazard support, they outspeed all base 100's, they can break all common walls, aren't on a 5 turn timer, and they don't take up that mega slot. Charizard needs hazard support and even then, even after you give it that support it can't even beat Chansey. I understand they're S rank but Charizard, who is imo a worse alternative is only one rank below, A+. Char-Y is overshadowed by the S rank wallbreakers on so many levels that I think it should be a couple ranks below them :/.
Oh look, Mega-Garde is a special wallbreaker in A- that doesn't need hazard removal, and beats Chansey.
Now let's compare it to other A+ rank mons. When you give Pinsir support it's the most terrifying SD sweeper in the metagame, and only gets reliably stopped by 1 common poke. Give Char-Y more or less the same support and you get a third rate special wallbreaker that gets switched on by Dragonite, the Latis, blobs... Both of these Pokemon eat teams for breakfast, but Pinsir has greater speed, can set up, has priority, andwallbreaks as well as Char-Y considering it also gets stopped by one common mon. What I'm trying to say is you get more bang for your buck by using Pinsir.
Based off my battling experience/the points above I've never seen Char-Y as an A+ pokemon.
Aight son you're telling me that Keldeo and Landorus break all common walls? That's so wrong. Keldeo needs to rely on specs to be any real threat to stall (Amoong and Venu will beat CM 1v1) and still there are SO MANY pokemon keldeo cannot break through without relying on a friggin 30% chance to burn.
Amoong, Venu, Slowking, Dragonite, Latias, even alomomola can take it on decently. You're REALLY overselling keldeo's power here.
I can agree that Lando is alike to char-y in that they are special wall breakers (and both part flying ?_?) but that's pretty much where the relevant comparisons end. The only real pokemon that they target in common are dnite and latios, and latios is pretty much 2hko'd by fire blast anyway. Sure, landorus has a way to "beat" them (only on the switch) but its not as if landorus doesn't appreciate pursuit support either.
Finally, you make comparisons to char-y with mega pinsir and mega gardevoir, saying that they have more power or require less support. Well, given that you keep rocks off the field, Char-y has FAR more survivability then all of them, and i'd say that's a big part of what makes it such a good mon. Fire/Flying is an excellent defensive typing and Roost is reliable recovery; thanks to these Char-y will be sticking around FAR longer than mega garde or Mega Pinsir will. Ultimately, Char-y's bulk is just better, which allows it more switch-ins, which allows it to wallbreak more efficiently than you'd think.
Also, if you forego roost and put in focus punch, you can catch chansey on the switch (or when it does almost anything else) and kill it with a fire blast following up :3