I don't suppose I could use it to shoot planets at enemy empires I don't like?
Maybe. We've considered that possibility amongst other fun (ab)uses but haven't finalized Fling's mechanical design yet.
Are there any plans to implement directional armor/shielding and the like?
Shields may or may not be omni but armor is likely to be directional.
Will ships require having those vector maneuvering thrusters, like in Nexus: The Jupiter Incident, or will they still have to flip around to do their whole 'thrust' thing?
They will have to do a burn on their anti-forward-velocity vector to reach 0 velocity, yes. We
may provide an option, as we did in SR, to force ships to face their target vector at all times rather than show where they're thrusting.
The reason for the flipping: If you want a ship to reach a destination as fast as possible but reach 0 velocity when it gets there, it'll be doing a full burn the whole way; half accelerating towards the target and half decelerating towards the target. Since SR's ships have their engine on the rear, the thrust vector has to flip to accommodate the second full burn. That said, it'll be in script format this time around so the community may be able to provide mutations (e.g. the classic ST-style 'inertial dampener' effect).
How much do you estimate it'll cost?
Price hasn't been decided yet but it'll probably be aggressively priced, as SR1 was.
Speaking of combat, will we be seeing any more cool fleet formations? maybe custom fleet formations?
Formations are going to be much more moldable than before.