I agree with you about preferring immersive single-player to multiplayer a lot of the time. But "would Citizen Kane be better in 3D?" is such a weird question -- it's hard to recognize it as such now, as much of what it does is now commonplace, but it's such a pioneering film in how it uses technology, and there's a lot of special effects in it. Who's to say Orson Welles WOULDN'T have found a use for 3D if it had been available to him?