Ummm dude, have you seen the same tournament. IG actually made Na'Vi simply become too responsive. Also, they kept picking the same heroes? I respect Na'Vi, and am actually a fan of theirs but they were just outdone by IG. Also what's a boring, Chinese DotA? This International has shown that the best Chinese Teams actually dominate their competitors with an even faster and more swift metagame than the Europeans. Simply a really big change from last year's EHOME.
Oh and for a simple analyses' sake, I'm gonna talk about the whole game.
Game 1 - Na'Vi doing some bluff game actually allowed Siren to be picked simply because they're prepared for it, and then pick it for themselves. But the TA and NS was just too powerful a steamroller for Na'Vi and the game ended in less than 30 minutes.
Game 2 - BOTH picked almost all the same heroes as Game 1 but with Lina and DK. In other words, Na'Vi to me are simply making their counter lineup more solid while the winner using what works (very understandable in a pro-game). Na'Vi won and ended the game in less than what it took to end Game 1.
Game 3 - I have never seen Na'Vi take Siren 3 games in a row but once again they use what works so they pick it with DK. What does IG do? Not what Na'Vi did in Game 2. They actually tried a different combo and to not be reactive to Na'Vi's lineup by picking Lone Druid and Disruptor as the main thorn to Na'Vi's side. Na'Vi was crushed but it took longer than 30 minutes.
Game 4 - You know what Na'Vi did? Become reactive and ban Disruptor. That there was the time I knew IG was in control of the mind games. Na'Vi never was this reactive to their winning performances nor did they rely heavily or even use Siren. Because of KotL pick of IG, they DID try to mix things up because they need the surprise factor and chose Nyx Assassin but it was in exchange for IG now having Siren and Dark Seer. Nyx Assassin didn't contribute as greatly as the Night Stalker of Game 1 and lost.
I am a Na'Vi fanboy but really now, kudos to IG for outplaying the defending champions and showing that the Chinese can be as swift and as unpredictable as Na'Vi. In some games, mostly in Game 1 and 2, they actually out-Navi'd Na'Vi by pushing aggressively and diving under towers during ganks.