I've seen it used in some MMORPGS's like Age of Conan, but I don't think it's really needed here (I don't hate the idea though). If we ever get thief (or something like it) you could give them flee I guess. Instead of speeding the character animation up you could give that increased speed an actual sprinting animation.

Now choco dash seems more apt for this game. Wouldn't it be a cool feature to raise your chocobo to have access to a sprint? It would just be a trade off really, some chocobo's run quickly, some at a steady pace, and others quickly in short bursts... hmmm... Chocobo racing at the Gold Saucer anyone?