It decreased by a fairly negligible extent relative to other Pokemon. He was used competitively for quite awhile with his Y form, not sure what you were watching. Not that it even matters, to be honest, but that is just inaccurate. No, no, no. Charizard was not on the cut list here on Smashboards, Pokemon Trainer was. And even then, most people ignored that he would likely be cut. I was one of the ONLY people to point it out and I had dozens of people argue with me. Anyone that conceded agreed that Charizard would remain.
I never stated that it did not, in the same way that Mewtwo is still going to be low priority, as he always has been.
That is true, but that same logic also applies to any newer Pokemon along the way. All 3rd Generaton Pokemon have loss popularity, but there are still some that were notable success stories like Blaziken and the Treecko line. Charizard was a successful Pokemon as well, but there is doubts on needing 4 Pokemon from the same Generation. We don't get more characters from Marth's or Ness's game for example, instead we get Lucas, Ike, or Robin. Or even we got Alph over Louie for Pikmin in terms of a alternate costume. Charizard entered Smash later and felt more shoe horned into the mix cause of the Pokemon Trainer gimmick that Sakurai had planned. PT wasn't that well liked due to the theorized effort that had to go into three playable characters wrapped into one with a frustrating exhaustion gimmick. People were speculating something from Gen 4 (Lucario) or the Gen 2 remakes. Though I think many were hoping for Blaziken even though it was starting to age. I don't think anyone really thought Mewtwo would be cut and Charizard wasn't brought up often.
Pokemon is really in a mess in terms of priority. If something comes up like time restraints or "too many reps," we may wind up losing anyone that isn't Pikachu. Fan demand brought Mewtwo back, he isn't out of the running himself cause he missed the Brawl and 4 (Base) train. Now that he is a returned vet, he may very well be on equal footing or better to Charizard, Lucario, and Greninja.
And I recall Brawl to 4 days where many fans predicted and thought Lucario would be cut. He'd obviously be low priority and cut for a new Pokemon. Instead we only loss the Pokemon Trainer package and gained one of his three as a standalone. I really don't understand why people think someone HAS TO BE cut in Pokemon. Pichu was a joke clone and Pokemon Trainer was a ill received, heavy workload gimmick. The only true shocking cut we got was Mewtwo and that seemed to be a case of them running out of time as Jigglypuff, Wolf, and Toon Link almost missed the train as well. All three of those were also easy additions compared to reworking Mewtwo for Brawl. Sonic was also a late addition, but he was obviously a major hype producer. For going into Smash 4, Mewtwo was already cut and likely wasn't seen as urgent as Brawl veterans cause that'd be brand new upset fans cause their favorite got cut. But he was the first addition into the DLC and was very well received. I wouldn't be shocked if he outsold anyone else. According to popularity graphs and charts that another user discussed with me, it also appears he is the second most played Pokemon Rep with Jigglypuff and Greninja following behind him by a decent margin.
I think things are looking best for Mewtwo when laid out, But I really could see everyone making it back or the cut (if made) being a toss up between everyone that's not Pikachu.
I still stand by saying that I feel the priority should be like
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Though to be honest, the one who would deserve cut the most would likely fall on Jigglypuff. Charizard was more iconic for Gen 1 and it'd suck to lose the only Mid Generation rep.