There are a couple of good ideas in the story, and quite a few bad ones. Picard getting a clone is slightly hokey but it could definitely work well if everything supporting it was strong. The core idea of seeing what Picard looks like when he is raised in a hellish environment instead of a utopian one is interesting. We could explore this and this is certainly a very "Star Trek" scenario. It's hard to give it much praise beyond this though. It's a series of scenes and ideas that are not individually terrible but have very weak connective tissue.
Right off the bat there's a super flimsy excuse for getting Picard into a dune buggy with a gun on the back so we can have a car chase (or more specifically, so that Patrick Stewart could do some driving because he lives for that shit IRL) and action scene. It's not a very uh, prime directive thing to do there captain, what with that planet being prewarp and all. They all start digging up bits of a Data-like Android, fly off the planet with it and reassemble it. It's working for the bad guy, which surprises nobody. Anyway at this point the ad hoc nature of the movie sort of rears its head. Thinking logically, this is an extremely contrived and massively convoluted method for capturing Picard that could easily have failed if Picard was killed by the dangerous gang of roving primitives, or if he simply didn't show up, or if some other ship showed up first, or if they decided not to reassemble the android, or if they decided to do so extremely cautiously and keep the android under intense security since the last time they turned one on it was evil. Anyway Shinzon's plan is basically to do all this elaborate shit so that he could capture Picard to cure himself of some genetic degradation shit he has, which realistically, Picard would probably have been happy to voluntarily help him with since all it is is a blood transfusion. He needs a lot of it, but with future science, Picard could have donated blood over a period of days or weeks, or used a some fancy future tech to help speed up or the process (transporters, anyone?). Shinzon's motivations for wiping out Earth with a doomsday device are broadly unclear, he has now transformed from potentially interesting and sympathetic character to psi-rapist and zero dimensional genocidal tyrant. It feels like Earth needs to be under threat just so there are some real stakes. No real logical progression, or good reason to connect the earlier parts of the story to the latter ones involving an attack on Earth. Just all this random shit thrown together.
Tom Hardy does a solid job of looking Picardish, but beyond that we don't really get to see the whole Dark Mirror thing play out. He doesn't feel anything like Picard really. I mean it is obviously silly they made him bald too just to hammer the point home, but if that was the only major problem it would be easily forgivable. Whatever. It's a poor movie.
