Next two job should be Tank and Heal
AST questline already give a touch on Geomancer, despite the skill animation share with WHM, i bet it is just a placeholder as 5.0 still would be a long long way
and no more branching, it prove to be a mess when come to balancing, just look at SMN and SCH
even if we forget about balancing issue, there was a Musket guild in limsa lominsa, it exist since 1.0 but when 2.0 hit ACN was add instead of musketeer, and MCH at 3.0, i have doubt SE have any intention to create another gun/musket type DPS before 6.0