There is a lot that can be done with adding new species, and with F2P it's likely we'll see new ones added (in addition to Cathar). Species unlocks are prime F2P "items."
New classes are going to be harder. Most of the basics are covered and there isn't an obviously missing class role or combination. It's also a lot of leg work to voice out a new storyline.
have they announced if we are getting cathar with f2p?