The feeling of not being able to kill something then being able to kill it after levelling up is over-rated. Level scaling is bad, the worst etc but not having level scaling is realistic? Why am I getting powerful and the NPCs are not? Some NPCs like animals shouldn't but if I'm learning new abilities overtime some NPCs should learn some also. They should have min&max levels but the difference shouldn't be just stat boosts like in Bethesda games, it should be new abilities, gear, even changed looks or how many they are as well.
Also story urgency is a problem in RPGs the most, instead of trying so hard to make it "seem" urgent,(you don't seem good. -no I'm fine really, eder. not loosing my mind at all) make it so the end boss gets powerfull as you "dilly dally" in the game. If you reach him early enough you'll have a weak end boss, if you take your time the boss will be more powerful, he'll be in a fortified place with henchman every step of the way etc. f.i. If the player has max level party in PoE's end battle, we could have met a more prepared Thaos; there could have been like 2 more statues and the way down there could have harder encounters.