Depends, really, on what role "affinity" does to a person's spell. If "A" rank affinity gives 100x, or heck, even 10x effective boost to the spells cast, then it's obvious to go with the A rank fire affinity guy. 😛You would think they would care about raw power, as well. But that doesn't seem to matter. If a mage has 5000 power and no specific affinity, I'm going to want him over a 1000 and A rank fire affinity