It's because Arkham Asylum created, or at least popularized, that type of combat system where you just hit a button and your character magically parries or floats over to another combatant, regardless of what they were doing previously or where they were, which, while nonsensical, looks pretty from a cinematic standpoint and was really fresh and novel at the time.
That and Assassin's Creed, which actually came out a year earlier.