Replay value completely depends on how good the game is in my opinion. If the game is fantastic, it will automatically have a lot of replay value because you will play it over and over again and still be having fun. If a game sucks, it could have all of the game modes in the world but will have horrible replay value because you'll never want to touch it again.
Of course, the amount of game modes a game has contributes to if it's good or not, so I may just be spewing circular logic. =P
Of course, the amount of game modes a game has contributes to if it's good or not, so I may just be spewing circular logic. =P