Actually there are not many mages but they do tip the scales.
I knew I was not making myself clear, mages against mages is fine but the average soldier he needs to know that there is a chance or he wont rush in. There should be a way that an army without a mage with them could win a struggle...
I am not sure about the booby trap ( it is kind of anti climatic too much D&D ) but the environment is something to think about... as a way for the mage to restrict his power.
any other ideas.
Have you ever read mordant's need by Stephen Donaldson? It is not the same but it does have something about making mirrors that show things that transport into the world things like dragons or earthquakes...
It is a really good series by the way...
I am not sure if any of you have read the Aspect emperor book by R Scott Bakker but in his books his mages are not just powerful they are really powerful but the catch is that there are these items (very rare ) called chorias that completely dispel any magic if it comes into contact with it...