>>21266745>bulbapedia defining the core seriesGame Freak could make the next game have 3 gyms and the second half of the game is just a giant middle finger to the gamers and it can still be a "core" game. Spinoff games by defininition never contain the ability to capture and train a Pokemon. it's always some other thing.
As long as you have "capture Pokemon" its a main series game.
What they *should* do is have 10 gyms, and you only have to beat 8 (although you can defeat all 10 if you want to gain the other badges). There shouldn't be any sort of villains until post game where you're exploring around and suddenly you uncover some huge plot. What'd be neat is if there were hints for it during the main game but you couldn't really do anything or find out much about it. What usually happens is that somehow what the evil team is doing is required to move the plot along so you can go and finish the game by defeating the E4. That shit has gotten annoying and needs to be altered.