I once heard that The Unit switched attention away from the military operations of the men to the lives of the women left behind at home, as a result of focus group studies. Soon thereafter, it tanked in ratings and was canceled.
I can't help but feel something similar must have happened to Lost somewhere within the last 6 years. When the show first started out, I got the distinct feeling that the many mysteries had meaning and rational explanations. (I believe that the writers themselves even said so.) Sure, the Dharma Initiative was a peculiar operation, but it explained some things. But this ending, I don't know... It smells as if the ending that was originally planned was scrapped because it offended too many focus groups. Perhaps the original story promoted that all mysteries are only a lack of scientific understanding? (Sufficiently advanced technology, and all that) Perhaps it promoted predestination? I don't know.
All I can say is that with this ending, something changed somewhere. The carpet doesn't match the drapes.