I think FPX would have lost to any team that has a dominant laner mid and a dominant jungler. Caps and Jankos can't compete with the Chovy's, Rookie's, Tian's, Tarzan's, etc. IG has Rookie which can lane bully doinb but Ning's form last year made him bad vs Tian.
The only team left that has a dominant midlaner and jung duo was SKT. So that is why I think SKT would have won vs FPX. Griffin also maybe since they share the same mid jung prowess.
Faker wasn't dominant at Worlds, he was terrible in knockouts