Oh, I agree. It's fine for the author to do it themselves (as long as they are not being forced to). It's quite another thing for others to do it, even as the 'rights holders'. And I would argue, this is another good reason why copyright should not extend past the life of the author.
But he wouldn't have approved of 99% of these changes. No way, no how. It's shockingly disrespectful of his estate to do this.