Why FPS should I be getting with Skyward Sword?

[Shonumi]

Your settings look fine, but have you tried using OpenGL and enabling the Vertex Streaming Hack (Graphics -> Hacks) ? It provides a noticeable speedup, and in many cases OpenGL is faster the D3D11 (with and without the hack).

Could you post some additional settings? Mainly Config -> General and Config -> Audio. Also, right click Skyward Sword in Dolphin and go to Properties -> GameConfig.