JE Sawyer has put up a post on his Obsidian blog talking about fine tuning RPGs. Check it out:
At work, I am often directly involved in an aspect of game design that not all designers really deal with: system and content tuning. This is the process by which system rules and content are adjusted to produce a specific effect for the player. E.g. you want the player to feel like he/she really gains a great advantage when he/she gets the raccoon tail in Super Mario Brothers 3, so you space out the frequency of raccoon tail powerups and you make sure that the raccoon tail's flight powers allow access to useful/valuable areas.
RPGs are often difficult to tune for a few reasons:
* There are a lot of statistics
* Many of the statics are derived/connected to other statistics
* There are subsystems that govern access to various abilities (e.g. class systems, racial abilities, etc.) that create a player desire for egalitarianism/balance between those subsystems.
This won't all be coherent, but I'd like to write down a few basic rules that I have developed over time.
* Avoid allowing a base value to be modified by more than three inputs.
* From a single value, avoid deriving multiple values in different subsystems.
* Do not create drawbacks that are "opt-out" for the player if it still gives some benefit to the player.
* When making trade-offs between items/skills/abilities, those trade offs must actually feel different in application or the player's choice isn't very important.
* Show the player what he or she is getting, even if they don't necessarily understand how the underlying math works out.
You can go to the whole post here.