anything that has the potential to sell 8-10m units is a system seller. We might not see a huge spike, but it helps to sustain sales and those kinds of games get picked up with a system. Galaxy 1 came out when the system was completely supply constrained, so we really can't gauge if it was a system seller. As for people saying "it is a sequel" we saw Uncharted 2 sell systems. Really the big games on the system are the system sellers.
Games that will only sell 1-2m are much less likely to be system sellers, especially when they've already released another game in the genre. Considering how different it is to previous versions I'm sure it will bring in some new users, but I wouldn't call it a system seller.