I remember when it released, there were a lot of heated arguments regarding whether or not it was a disappointment and/or overpriced. A lot of people contended that it was simply misunderstood and we'd see it's potential unfold over time. Here we are ~7 months later and we're still having this conversation.
Part of my frustration personally is that the arguments started well before its release, and before anyone but playtesters had it on the table.
1. The pilot abilities are still disappointing. They are, indisputably, inflexible.
I do not think that word means what you think it means.
Vessery requires you to build a list around him (note: his pilot ability seems far better suited for Rebels)...
A quick question for you: how many Imperial ships are there without target lock in their action bar?
...and Rex, PS8 mind you, benefits from shooting last.
No, he benefits from shooting at things without shields. You can meet that condition by having him shoot late in the round, but you can also accomplish it by simply being patient.
2. It still sucks at clearing stress and has stress-inducing turns... I think FFG really overcompensated for the white k-turn here.
That's pretty clear, at this point. I think it could be 1-2 points less expensive, or (very preferably) have white turns where it now has red. I would also have liked to see the generic Defenders at PS2 and PS4+EPT or even PS3/PS5+EPT, but obviously that ship sailed a long time ago.
A PS2 Tempest Pilot with Accuracy Corrector is a whopping 9 points cheaper than a PS1 Defender. I think the main question really is whether or not you need a small-base cannon ship in your list. I'm not convinced that anybody would choose it primarily for its movement dial and one more hull.
The TIE Advanced has a weird dial (no 1-turn or 1-straight option, only one K-turn at only moderate speed, and very predictable while stressed), and actually isn't a lot better at turning than the Defender (the 2-turn is white instead of red, but the Defender's access to a 1-turn is a big deal in a knife fight). And the Defender has the white K-turn, of course.
It's also true that neither Accuracy Corrector nor Advanced Targeting Computer is quite the equivalent of a native 3 Attack. Those upgrades are more like a half-step between 2 Attack and 3 Attack.
So when you jump up from Tempest Squadron + AC to Delta Squadron, you get an additional shield (making it typically survive 1-2 additional attacks), a dial that's at least no worse, and at least half a step in attack. It's probably not worth 9 points, but it's worth a fair bit. The closest comparison is actually a Firespray, which features better upgrade slots (crew!) and better durability, but even with the auxiliary arc it has to tote around a Large base with corresponding large blind spots and an allergy to asteroids.
It's not a terribly user-friendly ship, and I don't know that it's truly competitive at a high level (particularly the generics), but it does have upsides.