The way I look at it, there are three major types of "leveling" stats:
1. Allocate points to skills how ever you like.
The best example is the Fallout series - when you gain a level you X number of points to place into Guns, Speech, Lockpicking, etc, which allows you to make large leaps in abilities in a short-time, and allows very specific character builds (ex. Unarmed/Sneak ninja-type character)
2. Improve skills with use.
This is not technically an RPG, but the Jagged Alliance series would upgrade your characters' skills relative to how they used them during the campaign. For example, diffusing and setting bombs would improve their Explosives skill over time, and running long distances with heavy guns would improve their Endurance skill. If you had a medic character who rarely fired his gun, his accuracy would remain shit during the whole game regardless of his advancement in overall levels.
3. Level stats relative to each pre-designed character.
This is common in the Final Fantasy series and most JRPGs, where certain characters were pre-designed to be the tank, mage, or healer archetype whether you like it or not, and would level stats accordingly. Example - compare the stat growth between Steiner (tough melee fighter) and Vivi (black mage) in FFIX, you have very little say in how they grow.
Personally I like #2 the best because it is the most realistic.
1. Allocate points to skills how ever you like.
The best example is the Fallout series - when you gain a level you X number of points to place into Guns, Speech, Lockpicking, etc, which allows you to make large leaps in abilities in a short-time, and allows very specific character builds (ex. Unarmed/Sneak ninja-type character)
2. Improve skills with use.
This is not technically an RPG, but the Jagged Alliance series would upgrade your characters' skills relative to how they used them during the campaign. For example, diffusing and setting bombs would improve their Explosives skill over time, and running long distances with heavy guns would improve their Endurance skill. If you had a medic character who rarely fired his gun, his accuracy would remain shit during the whole game regardless of his advancement in overall levels.
3. Level stats relative to each pre-designed character.
This is common in the Final Fantasy series and most JRPGs, where certain characters were pre-designed to be the tank, mage, or healer archetype whether you like it or not, and would level stats accordingly. Example - compare the stat growth between Steiner (tough melee fighter) and Vivi (black mage) in FFIX, you have very little say in how they grow.
Personally I like #2 the best because it is the most realistic.