Tacked on MP or MP only?

[Veknoid_Outcast]

I enjoy single player games a lot more than multiplayer games, but I wouldn't want to see a complete break where consumers have to choose between single-player and multiplayer games. There are plenty of games with deep, engaging single-player modes AND addictive, rewarding multiplayer modes.

The greater problem, which you identified in the OP, is the tacked-on mode, whether multiplayer or single-player (much more commonly multiplayer). It typically adds very little to the overall package (in some cases it detracts from it) and it often seems like a cynical decision on the part of the developer/publisher to increase attachment rate.