To help myself better understand all the fighters we're going to get our hands on soon I'm going to look into each Squadron and try and see how it would best be utilized in our fleets. To start I'm going to look at the most unappreciated ship (based on the limited feedback I've seen in the few hours since the article dropped), the TIE/A.
We start with the base, non-hero squad:
What immediately sticks out about the Advance Squad? It is expensive, 12 points makes it the highest base cost of any Imperial Squad. 5 Hull makes it the most resilient Imp squad, but 3 attack dice is decidedly average.
Why would we want it in our fleet? It adds durability to our weaker, higher attack-cost ratio TIE/Lns. Maybe in a 3:1 ratio they could be useful there.
What can't it do? Cover TIE/sa. The Bomber has the same hull value, but is much cheaper and provides better anti-ship (arguably the more important) batteries. Cover TIE/In. They want to be shot at, that's what Counter is for.
All-in-all it doesn't seem like a genuinely great ship, but there is an intriguing combo:
Soontir Fel + 2-3 Advances. The Baron of the Empire's ability doesn't specify the enemy has to actually have the capability of targeting him to suffer from his effect. The advances have great durability and Fel grants them a pseudo Counter, also greatly boosting his own endurance by making him untargetable(ish). Escorting other heroes is a viable use of Advances as well.
Next:
Darth Vader :
21 Points for a 4 Dice (1 is Black) attack that can also damage with Crits (the only squad in the game that can do this, Bomber only effects ships), giving him an average of 3.25 Damage per attack (3 blue attacks give 2.25 damage, 1 black gives 1 damage, average). He also has 2 Brace tokens (a distinct disadvantage compared to heroes with a Disperse token).
What is he good for?
Escorting Bombers. I know I said Advances shouldn't escort bombers, but Vader's extra attack and ability to gain pseudo crits makes him work well with Rhymer or even other Bombers as protection against enemy superiority fighters.
Pairing with Fel. Even better than a normal advance, he can brace to increase his longevity, allowing even more use out of Fel.
All in all I think the TIE/x1 has an important place in the Imperial Arsenal, but it definitely requires a bit more thought than other fighters as to its use.