what if you can level up your favorite magic spells and if the spells level up according to your usage. for instance, if you use flame destruction magic several times, it will be adept level and the range and the damage of the spell increases. and for the case of fire ball spell, if you increase its level, you can charge the power and the size of the ball increase, and each level ables the character charge more, like a magic in Fable 3. in case of ice spike, you can cast more spikes at a time. conjuration will be changed in duration and the number of the possible summon atronach. if the magic system of Skyrim is like this , you can actually make more distinguishable mage character with details. like fire mastery mage expert in flame magic. or frost mastery mage expert in ice spike. so you have to chose and spend more time to be a better mage in specific field of spell you like. so each elements of spell should be developed and trained.