It's currently 1 round/level with no benefits from spell foci or otherwise, and a bard-only spell. The push for more support focused bards starts somewhere or just plain old utility, and I think making some changes to their unique or early spells (compared to others, such as clarity, lesser dispel, etc) would be good. But mostly I would love for Amplify to last longer. Besides the mechanics, it's just cool as hell to take and a bard having great hearing (even if from magic) is peak.
I don't think it's a good idea to give Bards turn/level detection magic, especially not right after changing the CV/CA duration.