NAF – New artifacts with unique properties.

From a multiplayer perspective, this is more of a disadvantage than an advantage, unlike in single-player.

I agree. Multiplayer is multiplayer, and story and logic are more important in single-player. For multiplayer, it not only limits gameplay but also creates unnecessary hassle in terms of copying maps from one computer to another. Single-player scenarios should be designed properly from the start, and then there won't be such inconsistencies. In many games, even in shooters (like Half-Life), there are many illogical elements in multiplayer, such as multiple copies of weapons that exist in only one instance in single-player.