I would suggest building balanced books and I would avoid thinking of Mage Wars in terms of TCG terms, like aggro/control/rush/etc. It's better to go into the game with a mind that is clear of the baggage of other games.
Basically, as long as you are generating lots of actions and lots of dice, you're doing well. Regardless of which mage you're playing, creatures are very important for that reason; they guard things, attack things, and aren't very easy to solve (except with other creatures). I always put a moderate to large number of creatures in my books and never regret doing so. Think of a pyramid when it comes to including creatures too; several level 1 and 2 creatures, a few level 3 and 4 creatures, and one or two level 5 and higher creatures.
Figuring out card amounts is not something you can determine through thinking/theorycraft; you have to just play and see what you need. If you really can't decide at all when building a deck, just put in 1 copy of whatever you're agonizing about; you can always add more later.