1-Did the modding community ask for this, or is just Valve/Bethesda?
2-Modding is done by amateurs in the sense that they are not covered by contracts and work laws; what happens when there are controversies between creators of a mod, assets being "stolen", ideas being copied, help gets uncredited, etc.? Is Valve going to assume the role of judge?
3-When the most succesful mods will spawn multiple clones (a la games on mobile markets; ie. Flappy Birds, Threes, etc.) is Valve going to intervene? Will they rule in favor of the "original" mod only when the same tech assets are used? Will they say anything at all?