I am not entirely without sympathy for the idea of a union modeled after those in e.g. Hollywood; I can see reasonable arguments on both sides.

But the guild that controls the medical profession has turned out to be a disaster of such epic proportions that I am stunned any sane person would consider it anything other than a grim cautionary tale. Any other setup would be better than that. (Beware of the temptation to let the high status of medicine influence one's opinion of the institutions by which it is run.)