I'm developing a damage formula for an RPG. I've checked many popular titles formulas for reference (Final Fantasy, Chrono Trigger, Golden Sun and Castlevania) and most seem to use linear functions.
My issue is that for linear functions, the % in which damage increases when leveling up goes down in every level. For example, when you go from Lvl 2 to Lvl 3 and damage increments 50%, however when you go from Lvl 50 to Lvl 51, an attack only does 0.5% more damage to the same enemy.
This coupled with the fact that XP to level up goes up exponentially in these titles doesn't make sense to me. So while I'm tempted to forgo this type of function for my game, I feel there's something I must be missing since many of my favorite games use them. Moreover I have played these titles and I never noticed this.
Eg: Golden Sun damage calculation is a simple: Damage = Attack - Defense. Pokemon's damage formula below is a bit more complex but absolute damage growth also decreases on each level.
Am I right to think in these games damage increases at a lower percentage on each level?
How do they balance the game so that levels are still important later on the game?