Penguin: I think that the Excalibur does have a lot going for it as an
interceptor. It's got better armour, better weaponry, better AB velocity, and so on. But, as a
light fighter, I think it would be foolish to replace the Arrow with Excals (and yes, I think it's pure folly to use light fighters as interceptors). Those extra 20 klicks mean that an Arrow could tail an Excalibur back to its carrier, but an Excalibur couldn't tail an Arrow back to the enemy carrier. The Arrow is thus far superior in the light fighter's most standard job, patrols. As is the Darket, incidentally. And both of them are more manoeuvrable, meaning that if they weren't being flown by AI, the Excal pilot would face a very serious challenge killing them.
Oh, and the Vampire is a better fighter but definitely not a better interceptor than the Wasp - it's 1500 klicks
slower .
Now, your remarks about torpedoes being not required in WC3 are correct. However, they do work much more efficiently than the Excalibur. The Excal has to survive the turrets, get in close, neutralise the turrets, and only then it can proceed to kill the capship. A Thunderbolt or a Longbow can do it WC2-style - stay out of turret range, get a lock, afterburner in, and fire the torpedoes. What's more, they have much heavier armour. I very much disagree with the idea that an Excal is more likely to survive a capship attack than a Thunderbolt or a Longbow.