They also said in the conference that mods will be able to added or removed from playthroughs at will, directly within the game. Now I may be wrong, but doesn't mean that they will only be mods without scripts? A lot of script mods can't always be added or removed without consequences. Textures, items, etc, can be removed pretty easily. But repeatedly adding and removing scripts is a great way to mess up your game and your save file, especially when you're on a console where you don't have as many utilities.