I think that the pen tool for trace can be useful for creating special elements movements with few keyframe; this tool have to be like pen tool in Adobe After effects that can be locked with a layer and this one can follow the trace.
Example: I have a small logo or a face that i would to cover with a blurred image; how can I place the blurred image that will follow the logo?
In After Effects, with pen tool, I can bring an high contrasted point and I can analyze his movement in the clip, this step creates a movement trace that I will copy on the blurred masked layer that will follow the logo that i would to remove.
What about?
Regards!