Have you ever encountered the idea that, if you level up and get +10 attack but then the monsters you face have +10 defence more than the previous ones you faced, leveling is utterly pointless?
I get the social pecking order of leveling. But in terms of gameplay it blows!
If you had a middle ground, like say a random 10% of the time you encounter an opponent from a lower level rather than a balanced opponent, then your +10 attack actually matters, because for once you ran into an opponent with +0 defence. Then you actually did get stronger, but the rest of the 90% of the time it follows the usual formula of delayed progression.