Facebook should consider having an opt-in feature for user-experience experiments that could have a high impact on important news reaching the general public. By having users opt-in they would be aware of the feature that they were opting in for and therefore there would be less confusion. Users could be made to explicitly either opt-in or opt-out of the feature being tested which would increase general awareness of the feature. Users should also be given the ability to upvote / downvote the new feature in favor of relying only on algorithms to infer whether a new feature is liked by the majority of users or not.
I totally agree with you. I would like to know if they actually have any reasons why they don't give people this option, because even though people could tend to opt-out in masses - there still is possibility to motivate them somehow. About the feedback, it may not be straightforward for the same reason that people tend to ignore it, so I guess they have it figured out already and I hope their metrics are set well enough to notice issues.