And not just out of nostalgia

A lot of people give the old Pokemon anime shit because it doesn't really follow traditions that came after it that were closer to the game, notably Ash literally being handed half his gym badges, as well as things like Ash being a dumbass but I think the reason the original Pokemon anime worked so well and was so popular was because of things like that. It was kind of random, it was kind of wacky, it didn't follow the games or typical training 100% but at the same time, that's what made it really work. Remember how gym leaders in the anime used to be kind of assholes until after they battled Ash, they seemed nicer? That's so much more interesting than "Oh hi there trainer, let's have a fun gym battle! I'm not gonna lose!"

Also, there's just no chemistry that can match up to Ash, Misty and Brock. It's clear considering how much of a bore Brock became over time. I know a lot of people consider Misty a bitch sometimes (and when I look back on it, the way she treated Psyduck was kind of mean) but they tend to forget that Ash used to shit on Misty just as much as she did. Some of Ash's funniest lines are when he's arguing with Misty. That dynamic is part of the fun.