If anything those tests make it easier to find subtle differences, which is good if transparency is the goal. I don't think that makes them fundamentally flawed. They are used throughout the industry, making results comparable.
Of course there are other ITU tests that work without hidden references, looping or even A/B comparison. They require a much bigger listener pool, are more expensive and take longer, thus used less often during development.
Of course there are other ITU tests that work without hidden references, looping or even A/B comparison. They require a much bigger listener pool, are more expensive and take longer, thus used less often during development.