Standard Fanboy defence #1: if someone says something you disagree with on a forum they're obviously posting on the forum because their system has no good games. A foolish defence being that you're posting on this forum which would (by your own logic) imply that your system has no good games either.
On topic though, "System Seller" is a very poorly defined concept and it is open to interpretation which can make any game (or no game) a system seller. Personally, I see a system seller as a game which continues to be a major driving factor for to people purchasing a system long after the game is released (and a 1 or 2 week boost doesn't count) and the only games this generation that qualify for this would be Wii Sports, Wii Fit, Brain Age and Nintendogs.