I don't think the Defender is quite right. It seems they left a lot on the design table that would have made it a truly viable ship.
Firstly, the PS3 Defender needed an EPT. Considering only the best of the best pilots got to fly them it is fitting. Having the EPT available means that they can take Outmanoeuvre the card that was all but made for them. By K-turning behind their opponents it forces the opponent to K also or be at a severe disadvantage. This is a win/win for the Defender.
Secondly, the system slot should have been on the Defender and not the Phantom. I am still puzzled why they did it the way they did by giving the two best slots to the Phantom, though maybe they figured the Defender would end up too much like the B-wing. With Advanced Sensors all of the red turns become usable because you can do your action first. FCS makes them scary on offense and makes up for the lack of action economy they currently have. Also some nice synergy between Vessery and other Defenders with FCS. Sensor Jammer would have been interesting too (but I suspect this was the reason the slot went to the Phantom instead).
If you didn't give it the System slot then it would have made sense to give it boost as a native action to allow for some change of direction while doing straight manoeuvres. I wouldn't give it both a System slot and boost for the points though, but I wouldn't have changed the points and given them 2 of the above 3 options.
For such an elite ship it is also odd that it got the PS1 and PS3 treatment, while the Phantom broke the traditional mold by getting PS3 and PS5 generics, odd again, though probably down to the ACD, which lives and breaths by PS.
The last thing that hurts the defender is just how much of your squad it takes up and thus limits your options for the rest of your squad. It's price seems too expensive to get away with just using naked Defenders (at 25 points maybe).
I think the Defender is a big misstep for an otherwise well balanced system. The potential was certainly there, but it seems to fall closer to the Y-wing and the Advanced for sheer usability, caused by a real lack of options.