I'm constantly at, or slightly above enemy level, making it very enjoyable.
Maybe it's because I catch a lot of pokemon (currently 5 full boxes at 5th gym) and get a lot of exp by that?
Maybe people who outlevel the game by 25 levels use traded pokemon in tandem with the ep share? Or something in the middle? Who knows.
@ bolded part: Yes, I'm quite aware of that. If, at any point, what I said sounded like more than just a suggestion one could try if he or she should find the game too easy, I apologize, for I intended it to be a suggestion.
All I know is at most I was only ever 10 levels above Trainer's Pokemon, and that was the Event Blaziken gaining boosted Exp.