I am very fond of the signature moves idea that I came up with for my combat skills. I feel that it allows for more diversification and will encourage players to think outside of predefined abilities. The bugbear in my soup is that I have a different method of application and advancement for each of the three skill sets. It makes things more complicated, which goes against my goals for the game.
To streamline everything, I will be switching my skills and special abilities over to the signature move style. In order to do this, I need to refine(read: actually make up my mind) how I want to handle selection and advancement of moves.
Here is the best idea I have had so far. When players spend their advacement points in a skill group or special ability, they have the choice of buying a new move or improving his or her current moves by 1. If the player wants to focus on improving one move instead of all the moves, s/he may place the new points from the other moves into the one move. No move may have a bonus that is higher than the total points in the skill. When the player places enough advancement points into a skill or ability to move it into the next level of skill(apprentice to journeyman, etc) all the moves that make the transition improve by one.