RDM BLM DRG MNK SAM: Their rotations will not change so much that Lv80 play will be an entirely different job. Your experiences with their current iterations will teach you transferable skills.

BRD MCH SMN: These are changing much more than the others. You will have to re learn the jobs when the expansion drops.


But personally, I don't think it matters which job you want to level. If you think you'll be playing it after the expansion launch, then there's not really a huge difference between learning an incomplete job at 50/60 and learning an incomplete job at 70. The real question is, when the expansion launches, would you rather have the jobs that you want to play already at 70, or is it okay to have them behind by 10 or 20 levels? Because the relearning experience will be about the same whether you're 50, 60, or 70. The sooner you get to 80, the sooner you can play and learn the job with its complete action set, so you might as well get them to 70 now if you have the time, no?