I see the intention to add some difficulty and make players develop strategical thinking to plan ahead and progress through the game but first you must know about this level cap order which is the very opposite people would naturally progress. (kanto>hoenn>sinnoh>Unova)
It ends up being more of an inconvenience than a challenge and makes players beg for mons because their last team was a little overlvled for the next league.
Again i'm not asking for a whole Storymode skip, only suggesting to save time from unnecessary time-consuming E4's leveling.
just let me use my lvl100 gengar,marowak,rhydon i put 200h on goddamnit i know ev,iv,nats,breedingblabla