I’d agree that’s an example of a bad mixed relay. For swimming, I’d drop the gendered 4x100 Free and 4x200 Free in favor of mixed relays, but leave the mixed medley gendered, since it makes more sense in that format.
I don’t agree there. If you have a strong men’s program, but a weaker women’s program, you don’t have depth. You have gender disparity in performance. Personally, I think mixed relays have the potential to be a more wholistic measure of team depth. However, as you point out, it doesn’t help if nations won’t take those events seriously.