I desired to say this in a different forum but I feel I should post this now. Being a wizard demands you think in abstract ways such as this, not every thought is going to prove productive. Playing a wizard is possibly the hardest character to play as that, most of thier spells are open to interpretation by the GM. It is the duty of the wizard to try and push the envelope and come up with some unthought of way of using a particular spell. I have played a wizard and rolled grease spell as one of my spells, thinking this spell useless I wrote it off. Afterwards I thought and found so many uses for a simple grease spell that saved our party from complete ruin time after time.
I never thought about what any magic character doing as being up for like interpretation by the GM but you're probably right. I know I never play them because their too weak in the beginning.