>>55713043gen 2 is designed with the assumption that players will do everything as soon as possible, which is not how anyone plays the game. you'll have six badges and be trekking to the lake of rage but the trainers will be balanced assuming you haven't even fought morty yet.
the low level of trainers also leads to a drought of exp., making it had to train up new members and an ordeal to put some extra levels on old members. which doesn't sound bad on paper, a lower level curve is not an inherently bad thing, but since new moves and evolutions require leveling up, you're going to be using first or second stagers with basic moves for most of the game.
also if anyone is telling you johto is hard, they're either lying or they're stupid. johto's not hard, just tedious.