Actually - the same is true exactly of Melee. Your traits are what make you ridiculous. You buy armor just like a casting-sovereign, and you don't need to find ridiculous weapons when you consider what you can shop for.
There are a few things to consider in favor of spells though:
1. Most damage dealing spells are ranged vs melee which is obviously up and close
2. Melee can be dodged, and Dodge itself can be significantly enhanced via spells, wargs, etc.
3. Stinking mud to keep the warrior almost immobile while the mage can teleport.
4. *Clink*. It happens.
5. Trained units. Warrior has to kill them before getting to the Mage. Not true vice versa.
Basically, if the Warrior on a horse with charge and the impatient trait manages to take the Mage out on the first turn, great. If there's any obstacle between him and the Mage, the Mage will have the advantage. Of course warriors have utility in a sense that their performance in battle is mana-independent, but mana isn't difficult to get.
Not that finding great weapons is hard anyways, when you consider there are around two dozen of them vs the.. 2 that exist in game that actually aid spell-casting damage? One of which you have to purchase in your Sovereign creation?
I.E. Your mage is *guaranteed* to have his best weapon from day one.
