Hey, i'm on your side with this! But with the way developers have been treating gamers lately (just look at Epic, charging 3600 MS Funbucks or $40US for weapon skins!) is what's leading me to these conclusions. I'm hoping Valve pulls this off wonderfully, but they're only one of few gaming companies left in which I can show respect towards. I just want that reassurance that this won't happen to TES, but my mind keeps floating back towards that saying... "Absolute power corrupts absolutely"; trite but true.
It has been suggested that the industry is moving towards a model that focuses on alternative revenue streams as a means of paying for the products they produce. By this I mean, that the purchasing of DLC would be something that could be used to boost the money made from a single game.
TES were some of the first to experiment with DLC, and we got Horse Armor. Yes, it was idiotic. Then they turned around and released houses with missions and other such content. Then they made Fallout 3, we got multiple DLCs that were freaking huge world extensions and mission packs. They have been moving in the best direction here, because they started the trend and are carrying it on to it's next stage, whatever that may be. Other companies, like Epic and CCP Games are still trying to figure out how this fits in. Thats why you get gun and avatar skins that cost entirely too much. That said, Epic and CCP did that with content developed in house.
I will admit that I don't know who owns the official rights to a mod after it is developed and published. I would Love to think that it is still owned by the modder, but there may be some obscure legal document somewhere that says it is then owned by the game developer or the site owner. That said, see my prior point about charging for some mods. Steam would have to convince modders to start charging for their product. This means, that the modder himself would have to say: "Yes, I want money" and then everything he makes will come with a price tag, at which point feel free to pelt that person's home with rocks... or if your impressed and think they deserve money for the work they put into their work, buy it. Totally up to you.
Another thing to consider: most likely Steams lucrative advertising contract will pay for all the bandwidth we need on the Steam Workshop.
TES and Steam working together is a good thing. YES this could become an embarrassment to both. But, if it does we are talking about people who often learn from their mistakes. Steam has internal issues, but that seems like an under-staffing thing more than pure incompetence. TES has done some questionable stuff in the past, but that doesn't mean they don't eventually put together a decent product. Still, it could conceivably be the signs of a total screw up. I just don't find it very likely.