Currently the Armada system does not operate under the "if you can shoot me than I can shoot you" doctrine.
Should it? The Rebel Corvette will move after the dice are rolled and the attack is made, so unless it is speed 0 it will be somewhere else.
I am also inclined to suggest that with the shoot and move mechanic of the game why shouldn't the ability to read/plan well be rewarded?
I think the process is somewhat abstract, the miniatures themselves are not to scale or the corvette would be able to fit into the Star Destroyers Loading Bay. So the shooting rules may seem strange at times.
Wrong star destroyer (VSD vs ISD), but yes, it's a sliding scale. In the end the models don't matter, we're really only gaming with 3 base sizes. I wish they would explain there reasoning for the "yellow dot system." Might make more sense to us in the end.