My answer is the same as last time. I'm going to play as all of them. Though when I saw SMN's new abilities in action, I got hyped to the point of where I said "Don't do this to me SE! I was planning on switching my second go to DPS job from SMN to SAM, and now you're telling me we can SUMMON BAHAMUT!?" Now I got to find a way to squeeze SMN in as my third typical go to DPS job (along with gearing) along side MNK and SAM.
PLD getting 1 or 2 AoE attacks (finally!) and that new cover ability that involves party members taking cover behind you convinced me to switch back to being a PLD main after being a DRK main in Heavensward. But already having the PLD tank mount, I'll probably stick with DRK into Stormblood. And then play as WAR a lot after so I can make progress towards the WAR tank mount.
SCH or AST will be my go to healer main for Stormblood. Have to play as each of them a bit into Stormblood to confirm which I'll be.