Instead of Shinzon trying to destroy Earth, he should have tried to destroy Romulus, after all that's who he was supposed to have hated. Then Picard would be risking his ship on behalf of a traditional enemy who had stolen his DNA to create the very man who was in a position to destroy them. It could close with the implication that a new era in Federation/Romulan relations was at hand.
That was Shinzon's problem. He did not only want to execute revenge on the Romulans, but on everyone because he felt abandoned. Especially on Picard. His megalomania was eventually his downfall.
I think Hardy did a great job.