There were too many homages and inside jokes for anyone other hardcore ST fans to understand. Same thing happened with Insurrection. There were a lot of inconsistencies also that were hard to come to grips with.
I don't understand how or why the Romulans would allow Shinzon to build a ship faaaar larger and more powerful than anything they had in their fleet. They apparently hated the Remans and used them as cannon fodder yet they allow one to rise in the military and have his own ship? I guess he could have been building it in secret, but I feel like someone would notice thousands of torpedoes and other ship building resources to be taken and a massive ship being built somewhere. It didn't add up. Maybe he built it after he took over, but I got the impression he didn't have that much time? I don't know, it's all a little inconsistent.
I think the story is there. Picard battling a younger, angrier version of himself had the makings of a very powerful movie. Especially when you have two A-list actors in Patrick Stewart and Tom Hardy. And I think the B4 aspect also really could have worked, Data struggling with having a brother that he could possibly have a real connection with could also have been powerful. And the final scene with B4, that could have been so emotional, but it wasn't. The people who made it didn't know or care enough to really make it strong and emotional.