Rain Dance fits in AC. Kingdra is limited to abusing rain and abusing rain only. Now it most certainly runs a more effective dedicated Rain Dance set, but Kingdra doesn't fit on every team easily and Keldeo works just fine for breaking opposing weather, like sun or sand.
FaceFaceFace: "Genesect is like the Terminator. Scary when he's coming after you, absolutely lovely with ridiculous punch-lines when he's on your side."