I'll start with what I did enjoy, then move on to the less impressive aspects of the film.
While the CGI was a bit iffy, I still found the attacks on the colonies both stunning and horrifying. Caprica seems to have fared better in the attacks than the other colonies, likely because Caprica was home to the most advanced society and thus the best location for the Cylons to create their new home world.
In a recent interview, Tricia Helfer stated we'd finally get an answer as to why all the Sixs are different. We really don't get a definitive answer to that mystery, but we do see it is the Sixs who choose to differentiate themselves. It's an interesting idea that doesn't get explored as fully as I would have liked. But it is another indication that all the models are programmed a bit differently.
Leoben fell in love with Kara's voice and, later, sensed her specialness because of her ability to fly a raider. Those revelations were both sweet and unexpected. It also seems the Twos were the tech guys among the Cylons. What I'm less clear about is a confusing montage of images envisioned by Leoben of he and Kara together in the future. Are we being told that, like Kara, Leoben is special and chosen by
I'm not sure how I feel about the new information regarding Boomer and her sleeper status. Before I believed she was at war with herself; her Cylon self fighting to get out, not to force her to carry out her mission, but to stop her because she had grown to love her human life. The last part of my theory was reinforced when Boomer stated she was happier as a human. But we find out it's Cavil triggering Boomer in and out of consciousness. It's Cavil and his plans for her she's fighting against. Still, we get a good basis as to why Boomer was torn the rest of her life. She may have felt betrayed by the human race, but she also desperately wanted to remain part of it. Only as a human was she the person she wanted to be. A person she loved.
The film provided clarity as to why it was the Twos, Sixs and Eights who chose to split from their fellow Cylons: love. Leoben's love for Kara. Caprica's love for Baltar. Sharon's love for Tyrol. But it was more than loving one individual, it was their interactions with humanity and seeing humanity's capacity for love. Even Caprica Cavil would experience this concept through his relationship with Sam. And one Simon chose to become part of a family. So why were the Ones and Fives unwilling to broker a peace with the humans? I think the key is downloading.
The Cylons have the ability to share each others memories. Sometimes it's a selective process (See the Eight in 'The Hub') and sometimes it's done for the good of the collective. Shelley Godfrey may not have been in love with Baltar, but she had an infatuation with him. No doubt a result of sharing Caprica's knowledge and feelings for him.
Simon killed himself out of range of a resurrection ship. Galactica Cavil had Caprica Cavil boxed. They didn't have the opportunity to 'infect' the consciousness of the others. Had they been reintroduced into Cylon society, how might things have been different?
While I approve of Simon FINALLY getting a storyline and one that gave us new insights into the character, I'm more than a little suspicious that Gianna, who we had not seen since the mini, suddenly had a very substantial role in no small part due to the actress being EJO's wife.
I loved seeing Shelley Godfrey again and finding out what the frak happened to her. I had assumed she went out an airlock and the only twist was Cavil made her do it, which she didn't seem too happy about it. It was a nice explanation as to how the Cylons were able to keep tabs on where the fleet was early on.
A subtitle for The Plan could have been A Tale of Two Cavils. I'm pretty certain no amount of interaction with any human or Cylon could have changed John Cavil's mind about humanity and his thirst for eradicating humankind. Still, it's fascinating to see that the Ones, like all the other models, were able to be swayed in their opinions. Caprica Cavil, unlike Caprica Six, certainly felt no remorse for what he had a hand in, but he also didn't see the point of going on with the mission. They were never going to be seen as better or more worthy in the eyes of their 'parents'. In fact, given their actions, the Five were likely to love humanity even more.
And the final of the good? THE ARMS OF APOLLO! It was nice to see you again, boys. :)
As for the not so good aspects of The Plan...
The continuity people dropped the ball. When Adama was giving his big speech to rally the troops, Lee was no where near Galactica.
The film cuts from Adama receiving the note about there being twelve Cylon models to Baltar in CIC, implying he left the note. This makes NO sense. Baltar wouldn't have that information. I wish they had just let that plot point go. (ETA: nicole_anell, my resident Cylon expert ;), reminds me that Baltar did have that information. I stand corrected. But it still doesn't make much sense.)
I fully support nudity and sex on TV when there is a point to it. While the bathroom and living quarters are shared by men and women, would they really walk around naked like that? Don't most people grab a towel when they get out of the shower? The nudity was gratuitous and ridiculous. But it paled in comparison to the creepiness of EJO directing his wife in a totally unnecessary graphic sex scene. Issues!
The almost complete lack of Tory was odd. I guess Cavil really didn't care about her either? :(
I was unmoved by Cavil's murder of John. Usually violence of any sort against a child affects me, but I felt nothing. I think the problem is a combination of an underdeveloped character and a character we didn't know and didn't have time to. (I wonder if anyone thought about recasting Boxy? It would have been a nice explanation of what happened to him. And he had a connection to Boomer who had a connection to Cavil.)
It's also hard to believe John's parents didn't want him. People were looking to build family units after the attacks and we're to accept that not only did his parents ditch him, but no other person wanted to care for him. Had they said he had only one surviving parent who was too traumatized to take care of him, I could buy.
There's something wrong with a universe in which John Cavil gets as much action as Lee Adama. And more than Sam Anders and Karl Agathon.