I dunno if that's out of scope or what kind of "vectors" you're imagining, but if it fits the style, you can already create any arbitrarily shaped mesh from a generic flat-colored region and use FFD/skinning on it.
If you're thinking vectors that use bezier curves, that's an entirely different technology than what the Spine runtimes currently rely on.
This idea has been suggested before though.
Also, generally, wouldn't you want it to be faster at runtime than in the editor?
