In theory I'm not entirely against the idea of paid mods. I don't necessarily buy that mods are more "pure" if no one is able to make money from them. And I do like the idea that people might invest more resources in mods than if they are effectively donating their time to the projects.

That said, things can definitely get complicated quickly once you start providing financial incentives. I think it's smart to require mod makers to go through an approval process rather than just make it open.