Those RPGs being...?
Legend of Mana had a feature with its newgame + to be able to have the monsters be lvl 99, but that game really needed that, even before newgame + it became too easy with blacksmithing.
I think something along the lines of either a difficulty enabler, or just a scaling difficulty feature with newgame + would be nice. Sure its nice to be able to slaughter monsters effortlessly, but its also nice to need to do more than just rubberband/autofire a single button in an rpg.