There has been some noise on the blogs lately about how much magic sucks in D&D. And by proxy how magic-users suck as well. Forgetting a spell after its cast makes no sense. The spell levels don't match character levels. You can't scale the magical effect up or down. Why do I have to waste a spell slot on Read Magic? Well, (pardon my bluntness) Waa, Waa,Waa. I say deal with it babies. Everyone who has played or will play D&D should do one thing first. Read Jack Vance's The Dying Earth. The way magic is presented in the book is what the D&D system is trying to replicate. Magic is not science, it is not technology and its not even an art. To summarize here is a few brief points on Vancian magic for those of you who haven't read the book (no story spoilers).
- Magic is a dying practise, there were once 1000's of spells now only about 100 are known
- Each magician jealously guards their spells and writes them down in a unique code
- Memorising a spell is like putting a ethereal creature in your head and casting releases it
- Even the most powerful mages can store only a handful of spells in their head
- The greater the experience of the magician the greater power of and number of spells
- Casting a spell requires only a few words and simple gestures ( ie no time at all)
I would say to try incorporating some of those ideas into the background of your game before deciding that the magic system sucks. Never mind balance. Just make it interesting.