Yes, that seems to be a priority problem. Does anyone have anything really against using magic or against not having magic?
I think, personally, magic and science would be at ends. Scholars researching magic and how it works would have little time to research gunpowder or angles, and vice versa. However if a nation goes halfway, they could enhance basic constructions with magical auras, like basic medicines with healing auras or crossbows with enchanted fire. Or maybe certain nations believe in magic, but it won't actually exist.
I'd rather not say if we will have mages and spells until I know who would like it and who wouldn't, but I know I could work with either.
On a related note, what about non-humans? I know I said they were ok, but does anyone have a problem with that?