But why do you think there has to be a Rebel equal to the T/D? Where is the Imperial equal to the X-Wing?
Why not simply give the Rebels another ship - either weaker or stronger - that fits better into this time and already exists? It wouldn't necessarily have to be a fighter itself, after all.
And this has nothing to do with my "sympathies for the New Order", but simply my appreciation for consistency.
I mean, of course it comes down to how you interpret that game, but from all I can see it's supposed to take place in the Rebellion Era, so personally I'd expect Rebellion Era ships there.
Not saying that your method isn't "just as good", mind you. It's not what *I* would prefer, and I've long since held the opinion that too many authors are inventing new ships and weapons and species when there was already something that would've served just as well. But with the EU kicked into the bin, there certainly is potential to populate that list anew, with entirely new creations.
Newly invented ships at least do not come with any "baggage" in regards to expectations from fans. Though I'd probably still wonder at the Rebellion having any counterpart for the T/D when it was supposed to be the most advanced fighter of its time. That is simply the baggage of the Defender.
The Closest counterpart currently in the game is the TIE Advanced - which is a pretty close match for the X-wing aside from reversing its attack/defence stats and giving it Barrel Roll. It's not a direct analogue but I agree there doesn't have to be a direct analogue. Nor is the E-Wing a 'direct partner' - it's just an 'advanced rebel fighter', and the most widely recognised such one.
The other official counterpart is the TIE Hunter - which is supposedly being brought into Age of Rebellion, so might well make it into the miniatures game.
The main reason the E-wing has come in? It's one of the better known EU ships, and the Dark Empire series one of the most well-known graphic novels.
If FFG limit themselves to just things referred to in books and comics set before the Rebels start calling themselves the New Republic, you lose a lot of shiny things - because they're the 'New Republic' by the start of Heir To The Empire .