First, allow me to congratulate the Cleveland Indians on making it to the World Series while missing 2 of their 3 top starting pitchers. Next, let me congratulate Indians manager Terry "Tito" Francona on his masterful use of his bullpen. Now let's get down to it. The best thing the Indians did was trade for star reliever Andrew Miller, but the real props goes to the New York Yankees who signed Andrew Miller to a 4yr 36M dollar deal prior to this season. Why is that a big deal? Because since Miller got paid he doesn't necessarily have a chip on his shoulder freeing Francona to use Miller whenever he seems like he may need a fire to be relinquished. So whenever the opponent has men in scoring position in the 6th inning or later Francona can turn around and bring Miller in and shut down the threat. The bullpen in Cleveland is good if not great and they have the perfect manager to utilize them in the way he has.
The biggest culprit here is the way players get paid. One good thing about the stats invasion the geeks have brought to light is there are new ways to measure a player's performance, but until teams start using those stats instead of the old grandpa stats like saves, wins, and holds to judge how much players should get paid players will demand to be put in the roles that will get them paid. Had Andrew Miller not gotten paid I doubt Francona will have the freedom to use Miller in the same fashion that he has this post season. There are other arms in the Indians bullpen, but they're stuck in the arbitration process so they don't have control over how they're being used. Once the arbitration process evolves, just like how stats have, that's when more managers will have the opportunity to use relievers the same way Tito is.