Probably just bandwagon mentality. I do admit that I'm a huge TTYD fan and it's definitely my favorite in the series, and imo the best in the series, but the other games (well, minus Sticker Star, I suppose) aren't BAD. I personally didn't like Super Paper Mario, but I know loads of people who did. The latest ones like Color Splash and Origami King have a lot of cool aspects, but I, along with a lot of others, just find them to be a bit bland compared to games like TTYD or even 64. What most people complain about is the unique species being replaced by generic Mario ones and Bowser constantly being the final boss instead of new characters, but that's not the games, that's Nintendo. I think Arlo did a video going over Nintendo's newer policies for that stuff. Unfortunately, that's just changing times. I love TTYD, but I know that we're never going to GET another TTYD, so I try and look at the bright side. Sorry for splurging, I just wanted to give an explanation from the side of the PM fanbase that doesn't hate everything