Classes are going to be rebalanced in 1.18, 1.19, and 1.20. Jobs are slated for 1.20 I think, and those are party specializations for classes.

We don't know when we're going to get any new classes but it'll either be when jobs are released (not likely) or a very long time after that. There are more important things to do than classes, like fix SP, crafting, and redesign the zones. New classes can come after that.