I don't think it would work very well if it were the people who agreed with a study to somehow also have the obligation to point out its flaws. Could we believe that they were being thorough in finding problems if the conclusions supported their own beliefs? It works better, I think, if the challenger takes an adversarial, but not actually hostile, position. And, of course, for both sides to have open minds, but I realize that is often too much to ask.