The 8-man group I'm looking forward to the most right now is Dark Knight, Warrior for tanks. Scholar and Astrologian for healing (Depending entirely on what AST brings to the table, may switch back to White Mage). Dragoon, Ninja, Black Mage and Bard for DPS.

I honestly don't see the point of a Machinist if the only buffs they bring are TP and MP Regen, we already have Bard who has them and Foe Requiem, and AST brings them as well.