Personally i loved pokemon during my earlier years, but as i grew older i strayed from the series because i had less and less time to get invested in pokemon. I remember criticizing the designs of black/white and coming to love them years later, now i take a good look at some of sword/shield's designs and i can't help but think that the majority of the pokemon created were created by different artists from the last games.
I've played all of the games, with the exception of eevee/pikachu. Here are my gripes with pokemon as of now.
Pokemon has lost it's "soul".
I've been reading into this, but over the years the flavor and definition of pokemon hasn't resonated with long time fans such as myself. Sure we get new pokemon, and a new story every once in a while is nice, but it isn't the same. This wasn't a long time change either, I'm willing to state that pokemon started to stagnate for a lot of people after black/white 2. The game was made much much easier for players in the later titles. Some argue that it's just the transition to 3d, but i disagree. A lot of neat designs came out of the later titles like sun/moon, but the core gameplay loop of the new games is altered in a way that is uncomfortable. HMs were slowly faded out, they were a pain sure, we can all agree that they took up vital moveslots, but they were essential for unlocking and exploring later parts of the game. It made you going back worthwhile, it gave the areas we explored in the first half of the game a second purpose. HMs are useless now anyways because a typical pokemon journey today consists of a linear path with little variation. The older titles gave you freedom of choice to explore and battle gym leaders in no particular order.
The Introduction of a party-wide XP share destroys any aspect of training your team. Leveling your team used to take thought and strategy. Now any moron with a type advantage can steamroll an entire section of the game and the rest of their team gains levels without even participating. That's not challenging, that's intended laziness. There's not even an option to turn off XP share (UNLESS YOU PLAY X/Y, BUT THE GAME NEVER NOTIFIES YOU OF THE OPTION IN THE KEY ITEMS POCKET OF YOUR BAG). If there was a difficulty option with XP share on AND off, i wouldn't have a problem with it. It forces you to think critically about your party and their stats (even though a large % pay no attention to their pokemon's EV/IVS anyway). I digress, as of sword/shield, there's absolutely no way of turning off XP share. Its hard baked into the loop now.
The introduction of mega evolutions was great, but they are (for now) thrown away for gigantamax. I don't really have an opinion on gigantamax, it's just a silly gimmick to give people some eye candy.
Also, something extremely nitpicky, but the starters loving suck. I'm not going to beat around the bush, they all lack expression and character. Like, from an artists standpoint, that's a really poor first impression of the rest of your roster. Also something else, why are all the final evos of starters anthropomorphic? I've noticed this throughout some of the more recent titles, your starters are either all bipedal or all human shaped. This wasn't an issue in past games, usually you had two on all fours and one bipedal or vise versa. They may have stood on two feet but they were different enough from people to actually still be considered pokemon.
Cinderace could literally be a guy in a loving fursuit, and none of us would be the wiser.
One final note. It doesn't help that sword/shield is a demo of what we were actually supposed to receive. Anyone skeptical about sword/shield would be interested to know that the success of pokemon go prompted gamefreak to make a mobile pokemon game with the intention of linking it with go. That game was sword/shield, but the success of eevee/pikachu also prompted gamefreak to port the game over to the switch. This was all planned from the beginning of pokemon let's go. If the switch pokemon game flopped, they would exclusively make games for mobile, but luckily it didn't and sword/shield seem to be doing well given the needed criticism.
I still stand by my statement that the heartgold/soulsilver/platinum games are the definitive pokemon titles that stay true to the formula without adding in a bunch of random bullstuff to pad time.