Good question.  What I would say is that we can build this into the roleplay itself.  If you want your character to be a spellcaster then if you have a broad idea of powers that you want your character to possess then DM me the details and I’ll say yea or nea - lets start with 5 potential powers that you would list and send over to me.

At various story based milestones during the game, and if you find the relevant trainers in the game to teach you the abilities you will gain access to them.  

To balance it out any non-spellcasting characters can list out 5 abilities that they would like their characters to access during the game at certain milestones within reason.  To use the example of the character already posted, Atyna, I would consider sneak and backstab to be abilities he could go for, and for Kian perhaps something like pick pocket to be one of his five abilities going forwards.

Does that make sense?