And what about the skeletal creatures, which they used in large numbers against Markel? And the green-skinned ones during the wars with the elves? Well, a child of Malassa is unlikely to be respected by the forces of light. And there's no one else left.
And even from one utopia, especially in the lands of the Unicorn, Vincent would hardly have gained the knowledge of the Academy (counterspell + knowledge stat). Maybe, then, the geography should be changed?

Skeletal creatures are one thing; they are undead. Godrik didn't use green-skinned creatures, by the way. I'm talking specifically about him right now. And it's not a fact that he would have fought against the black dragon. Godrik easily allied with Railag, while Faidaen had difficulties with that.
The utopia was in the lands of the Academy ;) And from a utopia, you can gain much greater knowledge than just a counterspell and a knowledge stat, in my opinion - you just need to "loot" it.