I know a lot of developers who are trying to bring a solid swing analyzer to the windows phone, that offers all of the features that you would find in a tablet. There problem is with the user controls that are provided for video playback development. The video control works great for "play", "pause", but there is a lot lacking as far a frame by frame.
I would have created an app for the phone already if the video control (media element) worked better. The above link I posted for my app in the windows 8 store is doing very well, even among golfers.