I would like to see some survey data, but one common denominator of most of the people I have known who have left the Church after being dedicated members for multiple years is an all-encompassing, black-and-white, absolutist view. I have seen it in kids with parents who fit this description and with converts who come into the Church with this perspective. I think it’s much more complicated that just that, but I think inflexibility will lead to either incredibly difficult struggles or a refusal to even consider different perspectives. In my experience, what it produces is either anti-Mormon fodder or simplistic generalizations, stereotypes and denial by members, since it essentially leads one to not be able to accept what one can’t understand - which is, at the core, a loss of faith.
This belief that everything is black-and-white (that everything can be "known" in the here and now) is what I see as a lack of faith among many members - what I see as the opposite side of the bitter, ex-Mormon coin. One refuses to accept gray areas and leaves; the other refuses even to consider gray areas and stays. In both cases, it is faith that is lost - or never gained in the first place.