Well, All that I can say is - start a mage on impossible and try your hand at the game. Well see if you can get out of the starting few islands without map guards kiting. With a warrior, you can do it - I did it. With a paladin, you can do it as well. With a mage, you have twice as less leadership than the warrior, no double casts nor lots of rage whatsoever to use the dragon to push enemies back 2 steps all the time.
I can go so far as to say that a mage can't even get to rusty anchor without map kiting on impossible, unless you luck out with several + leadership items - and still it is doubtful whether you will be able to afford them at all.
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