Building a Magic system

As we prepare to run Dresden Files for the summer, I've been thinking about the magic system for my novels. I mentioned it in an earlier post, some of the rules and considerations for magic in general. This time, I'm going to take a less structured approach, but instead discuss some of the things I've been considering for my own system.

In my previous post, I discussed three basic portions to a well-defined magic system: Source, Control, and Drawbacks. To this list, I'm going to add thematic considerations, and move forward from there.

Control
I'll start with this for no better reason than it's first alphabetically. In the first iteration of the novel, I had nothing but a pure expression of Will. From a magic standpoint, that's pretty boring. In the second case, I was dancing with ideas of Sympahty and Runes, both of which I discussed a little before. In the latest version, I've got a highly individual, varying expressions of control. I've picked mostly 5, but there's some room for other consideration.

1. Blade - This is a variation of the physical / dance expression of magic found in Marie Brennan's Doppleganger (I believe it's been re-released as Warrior & Witch). The energies are focused through combat (will probably include dance here). 
2. Bard - This one explores the magic of Song. 
3. Weaving - This might be weaving fabric, or it might be more general symbology. There's still some room for exploration
4. Herbology / Alchemy - This one is mostly for a single character, but a couple others can get some use out of it. This weilder makes potions, poltices, etc.
5. Smithing - The act of creating an object, and binding energies to it.

Some of these might get transformed with the Themes I talk about a little later.

Source
 The one thing that hasn't changed since this story's conception is that the source is elemental in nature. The elements also will be part of the expression of magic, parts of the themes. More on this later.

Drawback
This is the big thing. I've no idea what drawback I feel like employing. I've been dancing with a couple life energy ideas, or working out a weakening of emotion, but that seems...well dangerous. I dont' want to give my magic users cause to forget emotions, because then they'll all become psychopathic. So I don't think I want to go that way. Memory is cool, but I'd feel too much like a rip-off.

Themes
In this, I'm investigating the sorts of magical effects. That's kinda what I mean by themes here. As mentioned before, I really want to have the elemental effects. I was having a few other effects per person, but I've recently decided that each character gets general elemental control, one literal expression, and one figurative expression. I'm not sure yet how the first two will be separated in all cases, but some of them will be handy. For the character I've posted before, Jeshi, the element is Fire. Her figurative expression is giong to be the blood magic, which I've been workign on. It might not be as figurative as I wanted it to be, but I think it'll fit. Blood is the carrier of the inner fire, and as such is symbollically attached to a persons life force, and to their magic. My protagonist for the first book is going to be limited to Water, as much as I wanted fire as well. That was too mary sue-ish. The literal expression is going to be a mistform, which might still be mary sue-ish, but I think it'll work. THe figurative expression will either be traveling magic, or shapeshifting. While I prefer the latter, the former might be more useful. If I decide to limit it to one personal expression, then I'll drop the mistform.

So that's about all I've got for the moment, but I think it's a decent start.