[thejeff]

True, that's a good point.
I think it depends on stage of the game, though.
Early on you're just trying to get enough of your troops close enough to slaughter his. Other than a couple of SoS, your mages aren't going to do much for you. It would hurt to lose them of course. You'll probably be using indy commanders (Triton lords or whatever) to bring your troops in, so they won't be targeted by Fire Large.

With more research, keeping your mages active will be more important, but you'll have more gems & spells to work with.

I'll try it with Fire Large and see how the results change.