Didn't they already say they won't and that the expansion is going to be more of the same?

Well, I guess the question I'm thinking of was about making new job types rather than just tank/healer/dps, and they said they wanted to keep it simple for any new players that might pick up the game at the expansion. But you could likely extend that answer out to everything else. If a fourth job type is too complex for new people to grasp then pretty much everything is off the table.