Silent Hill would not be a good MMO for a simple reason. The theme of the game is a personal horror story. Making it multiplayer would drastically take away the spirit of Silent Hill. That being said, if you are looking for an MMO that is along the same theme as Silent Hill then I would check out The Secret World. You can check it out on Steam at:
http://store.steampowered.com/app/215280/.
I have been playing the game off an on since beta. (Even have a lifetime membership) It is a solid modern horror MMO. It is a hard game that does not hand you anything, and gives very rewarding missions that make you think and solve puzzles if that is your thing. If you do decide to get involved in the game and get to the end game I can hook you up with a friendly group of people that would be more than happy to help you get to the end game.