The thing is while on the surface Nemesis and Star Trek 11 similar, but if you dig deeper Star Trek 11 is a superior film.
Let's compare the villains for example, on the surface both Shinzon and Nero seem the very similar, both associated with the Romulan empire and both new villains with a genocidal desire for vengeance. However I think below the surface Nero is a way better villain due to consistency. There was a method to Nero's madness, since Spock failed to save Romulus Nero blames Spock for Romulus' destruction, he may even think Spock intentionally did not save Romulus. That's not rational, but it does make sense in a certain way.
With Shinzon I don't understand his motives at all, its like he changes his mind every 5 minutes and he is totally incompetent. He's mad that the Romulans enslaved the Remans, so he wants to destroy Earth. That makes no sense. He wants to capture Picard because he needs a blood transfusion, but he wastes a lot of time at the beginning of the film, instead of trying to capture Picard right away. Nero is a better villain because his goals don't change every 5 minutes.
Also the TNG crew did a lot of foolish things in Nemesis, if we are going to count mis-characterization against a film. Picard breaks the Prime Directive and guns down some aliens for no good reason and at the end of the film he endangers the entire ship by going over to fight Shinzon on his ship, instead of sending Worf or Date who would have a greater chance for success then Picard would. I wouldn't call Nemesis a crowning moment for characterization of the TNG crew.