Arcell I believe its more on the lines of "everything being instanced loses the server community feel" effect more than whether or not the dungeons are merely open or instanced. From my experience with SE they were always good at making a nice blend of the two (although in XI it was really instanced, but you get my point) and XIV so far has managed the same way.

I think people don't want to lose this nice balance the current game is holding and I really hold Square-Enix and the developers see these threads and make a wise decision on the matter based on what people are saying. I don't think anyone is purely against a "content finder" but I think people are against it when everything is instanced and it becomes 'required'.