Anyone complaining Valve gets a cut well so do the game developers too, any game developer is more to blame than Valve for this for opening their gates to allow modders to be paid, Valve just offer the platform to make it possible. The problem is considering it's the developers choice to allow this, are they going to be supporting all the paid mods that suddenly stop working because the Author doesn't want to maintain it any more and a new game version is released making the mod unusable, or when an official DLC suddenly ruins a mod, are the developers going to care? no, of course they wont.
Modders who move over onto the Steam Workshop just to charge for their mods are nothing short of greedy and somehow feel they're entitled to earn money from something they previously considered a hobby ( something they said only because they couldn't charge for it and didn't want to seem like an entitled cunt ), where before we used to expect nothing of them as they did it for free, yet now they'll charge for it, rather than just having a suggested donation, so are they going to be held accountable to the quality of their product just as a game developer and/or publisher would be?.
We can only hope any modder worth his salt will not go down this route and will provide the mod for free with a donation option for those who feel it's a good enough mod to be bought and if they've the money to do so. The worst part is that it seems to be a stupid move from some developers, especially Bethesda, because honestly as much as I liked their games, I can't play one without modding the hell out of it now, I certainly wont be paying for their next game if I've also got to pay for all the decent mods too.
It just feels like the next step in the cash cow business model, pumping out lack luster DLC's and profiting from user created content.
EDIT: Also, what about modders stealing stuff from other free mods and then selling it as their own? this system is gonna cause a lot of shit.