I don't think "Nemesis" was terrible, but I think there was a lot about it that made it a good, rather than a great, Trek film. The Remans weren't a bad idea, but since it was advertised to be the last TNG film, it may have been served better by focusing on adversaries that were more familiar. In addition, even those who may have gone to see the film that weren't huge TNG fans would have known at least something about the Romulans.