In my spare moments, my mind has been wandering in the direction of my wishes for a 4e d20 system that expands on the Book of Nine Swords.
Here’s what I’m thinking so far:
Each power would be located in a category (something like a spell school) and assigned a power level. It is conceivable that a single power might end up in multiple categories.
Magical categories could include things like Fire Magic, Shadow Magic, Healing Magic, Divination, Illusion, Necromancy, etc.
Non-magical categories could focus upon specific fighting techniques or skill sets (e.g., Swashbuckling, Lancer, Combat Brute, Unarmed Combat (in various styles), Stealth, Loremaster, etc.)
The trick will be balancing things like a non-magical Stealth category against something like Shadow Magic. I can think of a couple of ways of doing it, but I’m undecided. I’m leaning toward magic (1) having some thematic drawbacks and (2) being less flexible and repeatable. I might move a bit more toward ‘at will’ uses for mundane skills and ‘per encounter’ uses for magical skills. I’m thinking that one way of doing this is to have each power define its own refresh terms.
Powers would be of six types:
Actions are instantaneous (or near-instantaneous) effects initiated by the user. These are often attacks, but also include things like unlocking doors, turning water into wine, or catching a glimpse of your enemy’s thoughts.
Empowerment provides something (including, possibly, yourself) with a property it would not normally have. This includes relatively mundane things like inspiring a sense of readiness in your allies, as well as things like magically fortifying a door or increasing your physical strength. Magical healing is typically an empowerment.
Manifestations are typically magical. They create something – a wall of flame, an illusion of an army, or a gust of wind – that was not there before.
Reactions are much like actions, but they take place only in response to specific external stimuli. A featherfall spell is a reaction, as is a parry or riposte.
Rituals are complex and often consume both time and resources, but they may combine more than one type of action – or even more than one category of action.
Visages are similar to empowerments, but they affect only the user and may include drawbacks as well as enhanced abilities. They typically last for a significantly longer time than empowerments.