Look at this fabulously flexible result of rigging a face with the Transfer_AW plugin.
Steve @Shelton modeled this great character (right) and then we pulled out a lo-res version (left) with just enough splines to cover the essential landmarks of the face.
We rigged and CP-weighted that with some minimal bones for the jaw and lip corners and then used Transfer_AW to interpolate that lo-res rig to the hi-res mesh.
It would need some further fine-tuning but this is a huge time saver for rigging a face.
TAW Hans.mp4