## Which Stats? ##

First, with regards to what stats to implement, you need to work backwards from mechanics to derived stats to basic stats.  Determine what effects and mechanics you want during play, and determine how you want those mechanics to work with one another.  

The important notion when looking at relationships between mechanics is identifying the aspects you want to be [**orthogonal**][1].  This means which aspects are the atomic elements which are independent of one another.

For example, maybe you want misses and dodges in combat.  If you want these to be separate derived stats, you might have derived stats Miss % and Dodge %.  Then the question would be, should they be orthogonal?  Should a character be able to dodge very well while also being very clumsy and missing often?  If so, they should be orthogonal, and be based on atomic, independent basic stats.  If you decide they should be related (a nimble person who can dodge well should also not miss very often), they should be derived (at least partially) from the same basic stat.


## Hide Stats? ##
The question of [**blackboxing**][2] (whether or not to hide certain aspects of the system from the player) is a question of simplicity versus control.  Do you want to make the choices, UI, and overall game simpler for the player to understand, or would you rather they feel more in control of the stats of their characters?

## Multiple Classes or Single Class? ##
Finally, the question of individual Classes versus a table of variables for a single Class is a question of the level of difference between professions.  If the game professions are the same except for stat levels, a single Class is fine.  If there are fundamental differences in how the different professions function, multiple Classes might work better.


[1]:http://en.wikipedia.org/wiki/Orthogonality#Computer_science
[2]:http://en.wikipedia.org/wiki/Black_box