At first I thought so too. But now, spending a lot of time in this game, I must say that multiplayer is a bad decision. The main reason of this is that all of game's horror is built up on slow development of panic. Being alone and hearing branches fall, hearing strange noises is only catalysing paranoia.
Also this game (in my opinion) is not a full sandbox or full horror, but a merge between them. If to remove one of this genres out from the game (you removing horror element through multiplayer (because the main horror in this game is paranoia and panic)), then the game will become pretty boring. At least, this is my opinion