I played in a tournament over the week end and equipped my Vader with Proton Rockets. I was excited because with his two actions and 3 agility he should do some good damage.
It was the first time I had ever tried any range 1 missiles/torps. I didn't like them on the TIE Advanced.
As it turns out Darth Vader can do some okay damage at range 1. 3 attack dice + TL + Focus, you have a pretty good chance at doing 3 damage (before your opponent rolls agility) that should do some damage to just about anything.
At Range 3, though, Vader really struggles. Sure he will get his TL + Focus, but he can't get more than 2 hits. Most ships are going to get 3 or 4 agility to dodge with. There is a pretty good chance that Vader won't get anything throug.
If Vader Fires a Concusion Missile (he will probably have a focus) at range 3 he is likely going to get 4 full hits, and your opponent won't get any extra agility dice. So Vader is very likely to do some damage.
My critisism of the Proton Rocket dosen't mean that it is bad, it just doesn't improve Vaders damage output nearly as much a Concusion Missile does.
I haven't flown the proton rocket on an A-wing, but A-wing's like Vader are pretty good at doing damage at range 1, just not at range 3. So I don't see things being that different from the TIE Advanced.