You know what is the problem with pretty much all pokemon games in my opinion?
The story path.
You're never allowed to go where you are not supposed to go.
For example, i have a game going on right now on Silver Soul and i found my pokemons to be underleveled in 3 different gyms, the ghost, dragon and ice ones.
Now, the ghost and ice weren't that bad, you simply explore some more, find more trainers (i hunt trainers, i never dodge them and sometimes i read maps on the wiki to find them) and yadda yadda.
The Dragon gym was a pain in the ass though, with that level 42 Kindra and his One-ko dragon pulse.
Now im not an expert, my team have a Golbat, Feraligatr, Dragonite, Slowbro and Fearow, i realize that this team is not the best set up you can have but still it's my team, i level all of them equally and i put some effort in it.
For that fucking dragon gym i had to grind and jump all the map to challenge trainers i already beat, it was a real fucking chore.
Why can't i go explore Kanto before getting all the badges? Why can't i go in the caves with (and i quote a guard blocking me here) "Scary-strong pokemons" to train?
I mean training your level 34> pokemons with level 20-25 critters is a damn chore, it's grinding and i hate it.
Let me lose to unfair trainers and pokemons once in a while, what's the problem with that? Im not an idiot, i can learn from my mistakes.
I don't need someone to literally block me and tell me "Oh no this monsters are scary for you i can't let you pass", let me go in there and die like the dog i am.
I get it that they don't want you to be overpowered and level the field with the gyms and pokemon league but the solution is so simple, instead of capping my freedom cap my level: why allow me to have level 70 pokemons if there is no way i can obtain them for the time being OR if i obtained a level 70 pokemon it will spoil my game?
All of this does not ruin the game, not that bad but it is annoying sometimes.