Blizzard - Gamers Can Sell Their Mods Through Blizzard Arcade

Absolutely - premium DLC didn't prevent free mods being produced as well.

Getting mods to work properly can take more time than play the game. For me, the fewer, the better.

I always thought BioWare Social network was the perfect place to do this. Now Blizz has made it real.
This will guarantee a longer life-span for the game, plus benefits for the modders and the developer.

Wouldn't it mean the gamers' mods for say StarCraft? or maybe Diablo 3? would have to be rated by the ESRB, PEGI, USK, and BBFC? And also mean that Blizzard would need to test the mod internally as would Sony (ps3) and Microsoft (Xbox 360).

As I understand, this is why Bethesda hasn't allowed pc mods to become available for consoles as of yet...