Nemesis had some good ideas: Riker & Troi marry and leave the Enterprise, cool. They fail to get off at their stop, so they're there for the whole show, not so cool. Gratuitous psychic rape scene, not cool. Was that just in there so we could have Troi hold hands with Worf to get that revenge shot later in the movie?
Detecting a positronic android from parsecs away? So having Data onboard means the Romulans can find the Enterprise from across the galaxy? Finding out later that that the Romulans planted B4 there was still not enough explanation, and clearly the main reason for B4's existence was so an aging actor would have an explanation for why his character started looking old just in case there was ever a new TNG movie. As soon as that tidbit came out, I expected Data to be damaged to the point Geordi would transplant his positronic brain into B4's body at the end of the movie.
So they go to the trap, I mean Kolarus III. Anything like Belarus? It's a desert, with stereotypical ragtag nomadic badguys, and instead of beaming down, we get a cool new shuttle and a kewl new dune-buggy. Hmmmm. The generic ragged thugs chase them, they get away, nobody seriously questions how the android got there, who sicced the aliens on them, or how they detected the android from so far away.
Some Romulan politics - not bad, not great. Then the E-E goes to Romulus - ok, it helps credibility that they are asked for. Shinzon is not a bad idea, but poorly executed. Giving him a critically short time to live was lame. Nor does it make sense that he had to kill Picard to save his life. Now, saying his aging was messed up, and he needed a sample of Picard's blood to replicate to fix his DNA so he stops aging abnormally fast, but has a few years to work with - that i could have bought. What we got was too blatantly, artificially constricting, and robbed the character of any sense of being a dark mirror to Picard.
Nosferatu Remans? Logan should've been shot for that infraction alone. Donatra went from being a toady to a heroine with little explanation. Shinzon's great plan wasn't. Why does he want a war? How did they build this monstrosity with nobody knowing? Why did they use this uber-evil weaponized radiation so heavily? All clumsy, pointless ratcheting up of the threat without making sense. And then Shinzon takes a shine to Troi.
SMDH. One more failure, and bigger than all the others. TNG has never had a good movie, IMO, but Generations came closest to not failing.