In a reddit AMA a few months back, they mentioned that they recognized the issue to be the signal from the stylus to be too weak. They said they were working with a higher voltage stylus with a boosted signal, but i haven't heard anything about it since.
Knowing Microsoft very well...the solution for the surface pro 3 fix focus camera is the surface 3 autofocus camera.
The solution for the surface 3 and pro 3 wavy lines is going to be the surface pro 4.