I think it's fine to explain that a fic went outside your comfort zone and I'm sure you are very respectful in doing so. I do know that some people attempt to do that and come off as a bit judgey. "I never expected to like this kink" has a completely different tone than "I'm glad I gave this fic a try" but both are definitely better than "I so don't like this but you did pretty good." (You'd think that last is an exaggeration but it's not.)