So i remember playing a table top game called Weird Wars. It was a fun game where the Nazis discover magic and the allies are all "ohh hell no that's not good"... it was a lot of fun Mythral king tigers tanks were involved.
It used the D&D 3.5 rules. So a lot of cool things happen with guns being in the same place as magic. simply put the huge combat spells are all but useless. As the book says, why use fireball when a grenade does the same thing much more cheaply. In the same respect, some spells became amazingly powerful. Missile Defense became the best spell in the game because all bullets counted as missiles. The short of it is that mages became status effect and special damage throwers, along with the major buffers of the game. The standard soldiers became the main damage output for range. Only at high levels could mages start doing the huge damage spells repeatedly. At the same rate the riflemen could start doing status effects only at higher levels.
It strikes me that in any game where there are two ways of getting the same damage out there, they should really specialize in one group of damage verses another. Gunners can do the straight continuous damage but mages have the status effects.
This is me going crazy game designery.....