As I have learned, farrier schools offer a 2 week course which covers analysis or assessment of a hoof, trimming, anatomy, and putting a basic shoe on a horse. This is a great course for a trimmer, and is the equivalent of the first 2 weeks of farrier school. It could be a common ground, and a certificate for being a trimmer.
Eventually schools would have to commit themselves to giving a person an education that passes a test.
I think trimmers need to be noted as professionals as well. As long as there is only self study, and no guidelines, and not some sort of certificate that says you can do what you say you can do, trimmers will not be professionals.
I know farriers are working on it. The good ones are tired of the ones that don't know what they're doing . So they continue to press on about being certified.
What a can of worms!