Are you familiar Aspects from the Fate RPG system (used in games like The Dresden Files and Spirit of the Century)? If I can get my 4E campaign going again, I'm planning on implementing Aspects into my game.
The nice thing is that they can work out quite well for flaws, virtues, advantages, disadvantages, backgrounds, allegiances, arch-enemies, and more.
In a nutshell, Aspects are descriptive words or phrases, catch-phrases, mottos, etc, that are used to describe or define the character. The player may play on his Aspect in order to gain some bonus when an aspect could work in his favor by spending a Fate Point. A DM may invoke one of these Aspects in order to create a complication for the character, at which time the Player is awarded a Fate Point if he allows the Compel or must pay a Fate Point in order to resist the compel.
This works out fairly well balance wise, because players cannot reliably gain or use Fate Points without either a mix aspects that give them advantages or cause complications, or single aspects that can do both.
For me, I am planning on ditching the standard 4E PHB2 Backgrounds and using Aspects instead. I'll *probably* keep the normal Action Points, but there will be an addition of Fate Points. I will likely both award and invoke them in a similar fashion as SotC does, and come up with a list of types of bonuses I'd allow with these points (including minor narrative control).
Check out the
download page at FateRPG.com
Specifically there,
The Spirit of the Century (SRD OGL) that you will find there can explain Aspects quite well, for that game.