Honestly what would have made the movie better would be a different villain. Shinzon was poorly contrived. It took too much explaining to make sense, and the age difference was poorly explained too. The whole thing was more of a distraction than a central plot.
I think it would have been better if Sela were the main villain. They don't even have to go back and rehash the past episode in great detail. Just have it so that she lost all power and was imprisoned for the failed attempted invasion of Vulcan, and blames Picard and Data. We could also add Spock too, but whatever. What made TWoK's plot so accessible was it was basically a revenge plot.
Data's survival would not really change or benefit the overall plot which was horrible.