Introducing this into the modding community of a game that is several years old seems like a bad idea from top to bottom. I have no doubt this is just a trial run for Fallout 4 and ES6, but there are thousands of Skyrim mods, a majority of which use components of other mods to function, so suddenly you're in a situation where a for-sale mod using content from another mod will no doubt result in personal claims, who built what, etc.
Also, Skyrim, and most Bethesda open world games in general, are a precarious tower of code that runs most of the time, but is made much more fragile by the installation of mods and what order they're installed in. When you give away those mods for free, you can wash your hands of potential issues, but the minute you slap a 99 cent sticker on your mod, you are expected to support and to continue support said mod and how it interacts with the Skyrim environment in coordination with any other number of mods in the process.
This is something that, at best, should have been introduced in as future Bethesda game, and I expect this will introduce months of bad press for both Valve and Bethesda, which is already in full force based on Reddit and Gaf posts.