Actually, the underlying idea of the OTF is perfectly legitimate, in that, it is frequently useful to, as a thought experiment, imagine oneself as having started with a different perspective from that which you have in fact started. This is a point that I have argued many times. Where it goes wrong is when Loftus says that to *really* take the outsider test you have to take the perspective of an outsider like himself, a modern, science-oriented materialist. But there are many was of being outside of orthodox Christianity besides being outside of it that way, so why privilege that position? Why consider the results you get from that position to be authoritative or objective?
In short, anyone who thinks seriously takes many outsider tests, but what is questionable is when it is suggested that there is The Outsider Test (TM), the results of which are definitive for the rationality of one's belief. Also, I have argued that directing outsider tests to religious faith, and not to beliefs in general, is question-begging.