Agreed, it's highly unlikely in today's mass "fear-of-spins" flight instructing schools, but an enlightened individual who really comes to learn all about flying will naturally learn to do spins and all possible types of stalls. It is the natural process of learning to fly- to become the master of the machine - not learning a minimal amount to pass a rote test.
These individuals can, and should be, encouraged to become instructors, and not be discouraged by the naysayers who continue to huddle amongst the masses in fear of anything "out of the ordinary", or beyond the rote PTS and FAR requirements.
That being said, I would re-emphasize what has already been said, that the CFI Spin Endorsement is NOT a couple of spin demos, which is what the masses are doing these days.
The endorsement uses the specific words "is competent and possesses instructional proficiency in stall awareness, spin entry, spins, and spin recovery procedures..."
Getting proficient in stalls and spins isn't that hard. It's a stick-and-rudder thing.
Teaching it comes natural to some people. Even at the start.