What about Data? Does B4 become the new Data?
In the novel "The Needs of the Many", B4 does indeed become Data permanently and it is presumed he's the same Data in command of the Enterprise in the Countdown comic. Stupid, I know, but not any more stupid than Nemesis and the idea of B4 were anyway.
That's a bummer. I refuse to believe that Data would even transfer all of his knowledge and memory to B4 since he strives to be an individual. Nemesis fucked up a lot of things.
As I recall, Data downloading all that stuff into B4 was never intended to simply make B4
into Data, but to attempt to give him greater "mental" resources with which to find his own way. They did say during the movie that B4's lack of processing power and sophistication relative to Data would limit him. Additionally, I didn't take the ending to mean that B4 was going to "grow into" Data, since such a thing would be impossible (based on the movie itself having already told us that B4 could never be exactly like Data). I took it to mean that perhaps Data's hope that B4 could become his own unique individual - beyond just a practically brain-dead puppet - could be realized someday after all.
I'm not going to say Nemesis didn't have enough problems to fill two Galaxy-class ships, because it did, and B4 was one of them in concept. Adding another Soong-type out of nowhere was questionable, the role he played in Shinzon's plan was incredibly contrived (and, in-universe, so convoluted and reliant on chance happenings it was laughable), and no one even MENTIONING Lore during all of this was just
. But, the particulars of B4's brief appearance in Picard's ready room after Data's death... I actually kinda liked that. It's like, ok, this movie was full of problems, and this character was full of problems, but having him start to sing the song was a nice touch, and this idea that although Data is gone, some small part of him might live on in this other, unique individual... that seemed like good Trek to me.
All of that said, I
hate the idea that Data completely "comes back" within B4 (I guess whatever unique persona WAS developing was destroyed?), to the point where he's
captain of the Enterprise in the Countdown comics and STO backstory
. That is incredibly stupid to me, and tramples all over what was ONE little thing (that one scene at the end) in Nemesis that I felt was actually done
right. 
On a semi-related note: I second the praise/recommendations to read
Greater Then the Sum and the
Destiny trilogy, as they are excellent (the TNG follow-up to Destiny,
Losing the Peace, was quite good as well). Fortunately, in that continuing novel continuity line, Data DOESN'T return, and in fact, a really cool development involving B4 takes place in the (hard to find) novel
Articles of the Federation. Just yet another reason why the "main" novelverse is infinitely superior to the dreck that is Star Trek: Online.
