As I commented earlier, off-spec doesn't really mean what it used to back when we didn't have the dual-spec system. So I suppose we agree to disagree on that point.
Well hopefully the tank would be considerate of others' needs. If not, yes, I can understand the frustration it would cause on the DPS' end.
That, I do agree on. I believe that was another one of my reasons for opposing the creation of the LFR tool because while meeting up with four other random players can work out most of the time, I was and still am very skeptical about that holding true for raids. Despite all what I just typed, though, I probably will end up utilizing the LFR simply out of necessity. :/
Best of luck to us all.