Only Rogue/Ninja will be released in 2.4, I'm afraid - the expansion will probably be the time for new jobs/classes such as the Musketeer/Gunner (not sure which one is the right name). TBH they should have added the Musketeer before Ninja for the same reasons you listed earlier - we got double tank, healer, melee DPS, magic DPS, it would have felt only natural to add another ranged physical DPS; but the community strongly wanted Ninja instead, apparently.