Originally Posted by Taco John
Jamie is not even a prince, where Bran is.
Bran is not and if Jon and Dany were huge red herrings, it would be super anticlimactic for the answer to be Bran.
Jaime, on the other hand, wouldn't be anti-climactic at all (I mean, how cool would be it be if in the trial by combat, Jaime runs Brienne through and creates Lightbringer?!?!). His story has been the greatest redemption story in the series thus far. Jaime might absolutely be a Targ since they allude that Aerys may have had liberties on the wedding night to Tywin, so Jaime is much more of a prince than Bran could possibly tie himself to at this point.
The closest plot twists you'll get with Bran are as either a Dragon "rider" via warging or as a possible candidate to be "The Great Other" (how cool would it be if "Winter Is Coming" was a threat and not a warning, all along?)