Covering the upcoming classes and builds in Heroes of the Forgotten Kingdoms:
Paladin, cavalier (defender): The cavalier, first introduced in 1e Unearthed Arcana, makes a return. In 1e, I think paladin was retconned as a subclass of cavalier; in 4e, the cavalier is now a subclass of paladin.
The Cavalier build, like the PHB paladin, is a defender, so it’s probably a familiar-looking paladin with slightly tweaked abiities. Based on the etymology of the name “cavalier”, I’m guessing we’ll see a return of the paladin’s magical horse. Will we see the lance re-introduced to D&D as well? Please?
Do you hear that? The spirit of Gygax is trying to communicate with us! I think he’s saying “More polearms!”