It is, however, the only way to fire "while cloaked" unless you get passed a free action in the combat phase, after you have fired. Those are a lot of conditionals, is it even possible to do that in the game as Imperials right now (without ACD)?

Yep. I do kinda think that would be a bit too powerful on an Advanced though (especially Vader) - the Advanced has the advantage of higher base agility, plus great arc dodging abilities even without de-cloaking (well, Vader certainly does).

Isn't that kinda the thing about cloaking though? It's more about using the de-cloak to get out of arcs than about the increased agility, so if your ship is already good at that then the value goes down a little.

I really like the idea of de-cloaking and firing a missile, maybe one of those new ones that does extra damage when you have high agility.