See like, my thing isn't even an anti-Pokémon thing. It's one of my favorite franchises of all time, and I've been with the series since I can remember, even if the way Smash has historically represented the series doesn't always click with me and I have quite a few misgivings. There are numerous Pokémon I think would be awesome to see in Smash...what sucks is that those aren't the ones who'd make it in.
Gengar, Marowak, Alakazam, Snorlax, Ursaring, Scizor, Tyranitar, Gardevoir, Flygon, Metagross, Deoxys, Garchomp, Arceus, Zoroark, Chandelure, Golurk, Aegislash, Decidueye...all of whom are popular Pokémon who would be cool in Smash, will likely never be in Smash. Pokémon like Corviknight, Dragapult, and Falinks would be cool and are relevant, but they're not the type GameFreak would likely choose.
Let me give an out there example, using one of my favorite Pokémon: Sawsbuck. Sawsbuck would likely never happen. Unova missed its chance, and even if it got a character it wouldn't be Sawsbuck. But even Sawsbuck would be really cool in Smash. It's a deer, which have a very distinct and unique way of fighting that would translate really well into a fighting game, being essentially a quarupedal grappler. It wouldn't have a ton of ranged options and would be a somewhat large target, but could regain some HP with a successful grapple through its signature Horn Leech move. Strong burst options with Double Edge and Wild Charge exist, too, perhaps with recoil that would necessitate using Horn Leech successfully. And its seasonal forms not only show off something unique to the generation it hails from, being Unova's season system, but also work as alternate colors that are more flavorful than most Pokémon's while still being within GameFreak's strict guidelines.
Something like that would be full of flavor, showing love for the Pokémon franchise while also providing something that only Pokémon could give you (in this case, a grappler deer that damages itself with a lot of its powerful approach moves, but can heal some of it back with successful grapples). So it just ends up disappointing me when things like Lucario not having Bone Rush or Pikachu not having Iron Tail happen, or if we get "here's an Obligatory New Pokémon with Fire that kicks a lot. The only thing separating it from something from FIFA, Football Manager, or Inuzama Eleven is that it's on fire, an element present in some form on most of the roster."
Kinda went on a rant here but eh.