Boom! You've been ShamelessMcBundied!
Personally I'd drop B4 from the script as it's a cheap way to kill Data but keep Data. If you are going to kill Data kill him and be done with him! So no B4, no visit to planet, no Argo and no Federation armed SUV.
Next with Shinzon, his motives and actions are really just inane and stupid. If he needs blood so badly why not just make another Picard clone without the temporal juices? In DS9, Bashir grew a Bajoran clone in a couple of days. If he can get the resources to build the
Scimitar and create a magic ultimate weapon he can afford a chemistry set.
I'd also remove the threat to Earth plot and make it Shinzon and the Remans really wanting to destroy the Romulans. They are the ones that did a crap job creating him, they are the ones that decided that killing him was too much effort and they needed more child labour in the mines, they are the ones who have enslaved the Remans for generations. Shouldn't everyone be pissed at the Romulans and not helping them take done the Federation? They should have gone Hobus on Romulus's ass. If you really have to have Earth mentioned as under threat make it so that Shinzon just wants to destroy Earth so that the Feds and Roms. The Romulans already have serious issues with losing a war to Earth, imagine losing a second war, this time to the Federation!
Visually the movie is pretty. I thought that at some points the movie was just unnecessarily dark, as in poorly lit.
Oh, and the wedding at the start would be on Betazed so it would be naked. Maybe replace all male guests with Orion slave girls and have Riker stand behind a strategically placed fern.
After writing all that I'm not sure how much is actually serious and what is just rambling rant.
Thats what I plan to do, a fan edition of the Nemesis script but I need to know what fellow fans want.
Personally I'd say screw everyone else and make the movie I wanted but that's because I'm selfish.
Why don't you list out what you plan to change and we can say if we agree with your plans, add suggestions, etc.