I'm among those who find this movie so frustrating because it did so many things wonderfully well, most of them mentioned here. Even much of the basic plot idea could have worked. I actually like the idea of delving into the mysterious "Romii" world shown on the star chart in "Balance of Terror." A Romulan coup/civil war backdrop could have worked wonderfully. Picard confronting the much-younger clone of himself, who took a very different path in life that filled him with hatred and resentment against his progenitor. Riker finally leaving the Enterprise behind and moving forward to his own command, with Deanna at his side as his new bride. A meaningful, touching end for Mr. Data.
All great ideas that could have worked. Unfortunately the way they were put together just didn't gell. But wow, when I think about it, Nemesis could have been such a great film. *sigh*