1) Pokémon based on inanimate objects can be pretty cool.
2) Team Rocket (in the games) is a very one dimensional team. Later teams are better (except Plasma in BW).
3) Articuno, Zapdos, and Moltres are some of the lamest legendaries due to their weak lore when compared to later generations.
4) Platinum was probably the best pokémon game ever.
5) Cyrus is underrated as a quality villain.
6) I prefer "evil" Lusamine from SuMo to whatever she was in USUM. She was... I dunno... neevil? (Look it up)
7) I like the concept of the Ultra Beasts, but not necessarily how they were included in the plot of SuMo, USUM does a better job, but still not great.
8) Pokémon that lack clear facial features are weird. (Starmie, Nihilego, etc)
9) Rivals don't have to be jerks, but they do need to be interesting.
10) I actually really like when the plot centers around some regional lore and Gen IV did it best by incorporating most the the region's legendaries in the Galactic plot.
11) I don't think Pokémon ever needs to be an MMO.
12) I don't think there ever has to be a Pokémon game with all regions. Multiple regions, sure, but not all.
13) I actually really like the concept of Megas, Z-Moves , and Regional formes and how they can, hypothetically, make weaker pokémon viable (Mega Mawile, Kommo-O, Alolan Marowak). However, there needs to be more of a push to give those new mechanics to pokémon that have fallen to the wayside or to new pokémon. See #14.
14) As much as I like Charizard and Mewtwo, they need to stop giving them so much. They each got two Megas. If the armor evolution thing is real, and they also get that, then I'll be upset. I also don't want to see Pikachu get anything else for a few generations....
15) GOROCHU DOES NOT NEED TO HAPPEN. It was dropped for balance reasons in Gen I. Times have moved on and we have a ton of Pikachu-centric items (Light Ball and TWO Z-crystals) and mechanics as well as Alolan Raichu and its signature Z-Move. That is enough.