I disagree. It'll take the crown. There's so many more systems targeted for such a mainstream game.. Blockbusters are nice, but they tend to target smaller numbers of users and specialized populations. TBS may be a really niche genre, but if it can run on every computer, that's a much bigger potential market.
That said, it probably won't win in the press and the headlines, although it might at retail and digital distribution... And hey, not only did Sins win awards, it sold excellently, too.
Be honest, anyway, what wins? Warcraft expansions and The Sims expansions. Third place is wide open. Starcraft 2 and Diablo 3? Could do it. (although I'm not holding my breath). That would put it in fifth place.. certainly top 10.