Bolt the Cat
Bringing the Thunder
To each and their own I guess but I need to correct you on what I mean by split opinions, it's partly my fault for mis-wording it. The word I meant to use what diverse, not divisive. The sonic fanbase is divisive, split into mainly two types of Sonic fans. The Pokemon fanbase on the other hand is diverse in opinions, not split, not polarized, diverse in a range of opinions that say what their favorite or worst generation is thanks to the varying degrees of quality. I'm not saying the Pokemon fanbase is split, I'm saying that their is great range of different compelling personal opinions, such as yourself, from a wide variety of the fans that no one can truly come to a common agreement on how the quality has been raised or declined, or what is the best generation or the worst generation. This is proof that GameFreak has maintained consistent quality and care throughout the series. Perhaps it's declined a little but it's been quite consistent that GameFreak won it's fan loyalty. That is why almost everyone is excited for what GameFreak has in store of Gen 8 even though they haven't revealed much because it could be anything. Gen 4 we had the snowy mountains of Sinnoh. Gen 5 was the industrious cities of Unova. Gen 6 was the beautiful Kalos region that looked like it was out of a fairy tale. Gen 7 is a tropical paradise of the Alola region. People are excited what GameFreak has planned for the future, even when their not telling us because it's always a nice surprise.
Actually Sonic's fan base is diverse too, there's different groups of fans that like different elements of the gameplay such as speed, platforming, and exploration to varying degrees. The reason why SEGA's never really pleased the Sonic fanbase is because they've never really managed to balance these kinds of gameplay elements in a way that satisfies the entire fanbase. Most of them either favor either one element over the others or end up being a jack of all trades, master of none. The difference between Sonic and Pokemon's divisiveness is that Sonic's divisiveness is going to be difficult if not impossible to reconcile, balancing those three elements is a monumental undertaking that requires careful level design so that they don't interfere with each other and also provide enough content to be worth buying.
Pokemon's problem isn't that it's fanbase is unpleasable, rather, Game Freak simply refuses to acknowledge certain groups of fans and preferences. They only really focus on certain groups of fans, namely casuals and competitive players, and basically ignore everyone else. For the most part, additional content and gameplay styles don't really interfere with the current gameplay, they complement it in fact, so there's no real conflict in including it. Game Freak just decides not to do this and instead provides a bare minimum experience leaving much to be desired.