After character generation, the tendency is to immediately design your combat tables. After all, isn't that what most games devolve into - reasons to attack and defend. No matter what the game, this seems the basic element of most campaigns. There is even an entire subset of games where the element of character development is completely gone - miniature combat games. While these games can be a mind numbingly fun waste of time, teaching us strategy and tactics, they should not be the core of every single game.

The beauty of a role playing game, after all, is the role playing. And rules that you develop should be there only to guide, not constrain, the role playing. Instead of combat tables, there should probably be a simple method for determining whether an action can be performed, whether that action will be performed well, and what the outcome of trying that action would be. In almost every action movie, you see some neophyte handed a gun and told to point and shoot. The neophyte usually does it wrong - but really, how hard would it be to point and shoot? Ultimately, its the same action performed thousands of times on video games, or when pressing the buttons on the remote. My point is that skills and abilities need to be redefined into a sort of basic category and a genius category. Anyone can throw a punch, bite, kick, etc... but knowing karate, on the other hand, would be complicated and have to be learned. There should be a realistic number of these skills that a character can learn in their lifetime, but an unlimited number of basic skills (running, driving, swimming, etc... things they may not be Olympic caliber at doing, but could still do).

I think the skills available to learn should all be related to the tasks at hand. I.E. A ballerina knows ballet. She may know choreography, modern dance, fitness training, nutrition, etc... She is unlikely to know Explosives, or Aerodynamics. We should allow this ballerina to know these skills if she likes, but there should be some penalty in her character development as a result.

Using the skills should be then based on only three factors, the difficulty of the task, the experience of the performer, and the logic of the situation. (No neophyte hopping into a helicopter and rolling a lucky 20 and somehow managing to fly the helicopter to safety ;)

Anyway, a cohesive game system should encompass all these things together at the same time and not separately. Character development should be impacted by skills should be impacted by the way skills are used.

I hope that's clear as mud.