the difference is, faker has played like 40 games in diamond/challenger as mid riven wheras Hai hasn't played riven at all really on a high level. so still, it's ranked mentality. you can 1) pick a counter you haven't played much but people tell you is a good counter or 2) play a champion you are comfortable with and try and break even in lane. And even though gragas is medicore vs kassadin, i feel it was hai's best pick given the conditions.
Game 2 C9 got the right picks out of Fnatic and really played well. They still didn't get any specific champ snowballed, if anything hai dissapointed me, but he was a team player and instead of snowballing himself went in on the carry, sacrificed himself and let balls/sneaky clean up. It was well played by C9 and game 3 will be somethng to watch.