You seem to have information that I haven't seen. All I've heard is that new jobs start at level 30 (and require no base class), new jobs are unlocked in Ishgard, and you need to complete 2.55 (and register the expansion) to gain access to Ishgard. They may have a change of heart, but last I heard playing through any MSQ before 3.0 on a new job would be impossible.