Very close to where I would put it.. I might add a System Upgrade slot as they were at least as advanced as a B-Wing, and I would give it a Cannon slot, as they were quite often equipped with Ion Cannons.
I don't think it would be over the top if it was.. EPS (on some pilots), System Upgrade, Cannon, 2x Missile. You would rarely use all of the slots but it would give it options.
I agree that these upgrades make sense thematically, but I worry that the cannon upgrades would be game breaking. Autoblaster and HLC are balanced on a B-Wing by its lack of maneuverability/speed. Putting them on an Interceptor dial becomes troublesome. Is there a way to allow only an Ion Cannon upgrade?
System Upgrade should of course be included, that was an error on my part.
The Rebels wouldn't get a ship similar to the Defender because none exists. The Defender is far and away the most advanced starfighter ever made. OP's original stats were not arbitrary, contrary to what some here like to claim. They were derived, quite clearly and linearly, from the original TIE Fighter (video game) stats. The Defender was designed to break the game. It was so bad, that later versions, expansions, and sequels toned down the stats. That's why OP was talking about their inconsistencies. (At one point I think the Defender was unplayable, and if you tried, you got a message like Dream on Rookie, this ship is too powerful for you, or some such).
The problem isn't the Defender's stats, it's the game engine here. With all due respect to FFG, this was not a well-designed game. Tabletop game, that is. It's a board game (with some fantastic playing pieces). It was designed to keep the math hidden and use a narrow range of values, and add diversity via special-case rules (the same problem that plagues GW offerings, BTW). It does a good enough job for what it's meant to do. But because of that, any legitimate version of the Defender is going to break the game. It should have stats higher than anything else, it should cost a ton of points, and in a 100pt game, it very well could be the only model on the table that that player gets. Per the sources, it's faster than anything, more maneuverable than anything, and more heavily armed than anything, and has heavier shields than anything. It's a munchkin ship. It is never going to fit right in this game.
I think you make a strong point, but it seems that your argument is backwards. It is not FFG that has a poorly designed game, but rather TIE Fighter. As you say, the Defender broke the game. What FFG does is give us representative stats that allow us to use certain fighters in their intended roles, rather that debating about mega-joules and relative laser/shield/engine power.
Squints are designed to fly fast, hit hard, and duck return fire. 3/3/3/0 with their dial gives us a dogfighter that does precisely that.
X-Wings are meant to be a bit slower, swapping their maneuverability for durability. 3/2/3/0 gives us that.
B-Wings are tanks and Eyeballs zerg, etc...
Defenders are meant to be tough, fast, and hard hitting. Something like the 3/3/3/3 that I have proposed gives them all of these traits. Is it double an X-Wings power? No. Does it mean that the lasers aren't actually twice as powerful? No. 3 attack die gives them a decent chance to one or two shot most enemy fighters; especially if they have missile or cannon upgrades. Regardless of how powerful your lasers are, ships still have a lot of hull. Maybe the Defenders lasers chew straight through a X-Wing's wings instead of just scorching them, but as long as the wing is out of commission we can scratch off a hull point. That's the great strength of the engine as presented by FFG. It can simulate the general effect of a dogfight, while we can fill in the blanks mentally. The Defender can be the best fighter in the game without needing to take on entire enemy fleets on its own.