I don't see why it couldn't work. As for introducing new mechanics, it depends really. Some people like them, some don't. Expending resources in whatever form to enhance a spell seems ok so long as it all equals out.
Now, consider Wotc's newer products, especially the Eberron books. We now have spells that work better when cast by particular races, (Insidious Insight cast by a gnome has a +1 caster level) and spells that are better when cast by someone with a particular birth mark, (spells in Magic of Eberron that are more effective when cast by someone with a particular Dragon Mark).
I'm not sure how I feel about these kinds of spells. Never-the-less you should do what you want with your writing.