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.
Maybe, but people's egos alone are enough to causing issues in the mod community, I'm not sure paid mods are necessarily going to make this significantly worse.
One or two egotistical modders don't ruin the entire community unless those are the only modders in said community.
Greed ruins everything, though.
Not only would once free mods suddenly have a price tag, you're gonna get a lot of bullshit shovelware mods flooding the scene trying to capitalize on the market.