I get the feeling that boost should have been native on the defender, for at least the same cost. It seems overpriced and the boost gives it the option of adding some slight change in direction to it's green straights. I also feel that the system upgrade was misplaced on the phantom and much more fitting to the "top of the line" defender allowing it to use advanced sensor to BR or Boost either before or after it's long green straights, or white K.
I'm pretty sure I would almost always want to use engine upgrade on a defender and it just makes it horrendously expensive.
If the E-wing is a combination of the X and A-wings I would have expected the defender or TIE-ultimate as I like to call it, to be a mix of Interceptor and Advanced, but it falls a way short on the manoeuvrability. It's a very unique dial, but also extremely limiting.
I forsee people using cards from the set a lot, but no actual ships.