I could see Larian swapping out Goliath for Dragonborn for a "bigger than human" character option. The benefits would be that they wouldn't have to adapt armor models to the DB body-type or create a variety of unique DB animations including faces, gaits, and lizardy tail-related things.
Other than that, I'm skeptical of any other non-PHB races being introduced.
Of classes and sub-classes, obviously, Monks will be introduced. I think non-PHB sub-classes are very likely, although it's pointless to try to guess which ones. The PHB is far too sparse for sub-classes, in my opinion.
