I've been trying to go through how I feel about this.
I rarely download mods. I think the last one I tried was the World of Ice and Fire Conversion for Crusader Kings 2, and that was about 6 months ago at least. I went back to playing the real game after two or three tries. All the same backstabby and crazy dynastic fun combined with better integrated mechanics.
Anyways, I think the real reason I don't download mods very often, beyond having a huge back catalogue I should be playing, is I just don't want to deal with all the "mod" issues. So, when I do download a mod, its usually been "vetted" by magazines or a lot of reviews, and it is improvement over the base game. Thank you whoever fixed the inventory in Skyrim!
So, if I very rarely deal with mods that are free, why should I care if people are now asking money for them? They weren't getting my money before, they won't get it now.
On the other hand, there is definitely an opening to get me to pay money for mods. Remember, I don't do mods, generally, because I don't want to deal with the possible installation and other tech issues. If a company tells me a mod has been "vetted," that is to say it has been play tested and is gaurenteed to work with my game, I'd be more interested. Actually, wasn't half of Beyond the Sword including some of the best mods from the community? I Beyond the Sword currently sits as my best PC game of all time. http://www.quartertothree.com/game-talk/showthread.php?75874-Your-Top-100-Games-Challenge&p=3643276&viewfull=1#post3643276
Now, reading through this thread, I find the arguments against "paid mods" to be pretty persuasive. It is a company trying to combine profit with a lack of responsibility. If you want to make money from something, you have to be willing to be responsible for it. I don't care if you are selling fertilizer or antiques.
Well, LoL is a completely free game though, right? I suppose people see it as a way to game for free and in exchange somebody overpays for cosmetic content. For $60 games, consumers don't want to feel nickle and dimed after their initial purchase. They are willing to spend more on "gameplay" add ons, but not cosmetics. I can certainly buy into that reasoning.