One thing I like having the luxury of doing in an RPG is, instead of fighting 100 battles to gain a level, fight these elite monsters instead. They can be way, way more powerful than your typical mobs and reward way more experience. Ideally, they would be in some way easily controlled as to when you encounter them, so that you aren't randomly encountering unbeatable monsters. Final Fantasy 1 had an area like this where you could potentially encounter roughly level 15 enemies like Zombie Bulls and Trolls when you were only about level 5 or 6, and you might manage to win the battle by unloading all of your highest level spells and getting half of your party killed. For the few months that I played WoW a long time ago, I was also grinding higher level monsters instead of equal-leveled monsters, and it may not have been the fastest approach to leveling, but it was a strategic gamble that should be available to the player. Whenever I replay a game that I've already beaten, I like the opportunity to fully exploit the strategies I've learned to progress through the game way faster, and this is an angle that makes that possible.
So I tend to like having this in most / every RPG I play where there is experience / levels. Try to include it in your game, I say