I finally got to see Star Trek: Nemesis yesterday. I talked Sean into going with me. We had a great time, and we both thought it was a good movie, and that it could have been better. FYI, fanboy shit ahead.
First, the whole Shinzon/Picard plot was interesting only briefly. But after the third "I am your shadow/You are me" speech, I wanted to scream at the director "I get it! It's nature versus nurture! Move on!"
Second, the Data/B4 sub plot, intended to mirror the main plot, was not needed. This is what happens when an actor pitches story ideas.
Third, the Romulans were ill used in the movie. The screenwriter had set out to do for the Romulans what the earlier movies had done for the Klingons. Then he creates a new race to replace them! WTF?!
Here's how I think the movie would have been better.
First, replace Shinzon with Sela, the alternate Tasha Yar's daughter and lose that whole nature/nuture thing. Pre-release interviews kept repeating that they needed a worthy villian, like in Star Trek II. Instead of bring back a villian from the show, the create a new one. Sela had the motivation to destroy the Federation. Picard ordered her mother to her death, and then later, with Data's help, thwarted her plan to take over the Klingon Empire. Later, Data, Picard and Spock prevented the Romulans from taking over Vulcan. That's motivation: revenge. Shinzon's motivation? "Picard had it better than me." You could still use the Remans, and their motivation for following Sela.
Second, lose B4. Granted, that was a good way to get Data onto the Romulan ship, and it makes sense that there was a less "mentally" advanced android before Data, but there was no explanation as to how they found B4. As far as we know, he could have been a Romulan creation. instead, have Sela reuse the technique that the Romulans used to have Geordi become an assassin, and apply it to Data.
The space battle was cool. Well worth the price of admission. Go see the movie. It was fun.