By now I assume everyone on this board has heard the news about the Phantom and the inclusion of Debris tokens for tournament play. Since I'm one of the resident TIE Defender nuts, I immediately started thinking in terms of ramifications on it. With the Phantom having to pick its decloak before anyone moves, it isn't quite as responsive as it was before, but it still hits like a brick with the 4 attack dice and options for Gunner and FCS and the like. ACD still makes PS important, but not nearly as significant in combating the ships, and the lethality of the Phantom is somewhat reduced because it cannot adjust to enemy movement as well. Furthermore, the inclusion of Debris Fields in official games allows one to bring up to three large obstacles (large rock and 2 large Debris Fields). Both types of obstacles cause problems to action-dependent ships like Soontir Fel and Darth Vader as well as Phantoms. It's a subtle change, but might have an impact.
So why does the Defender care? Before April 15th, The Defender had a hit point and Cannon advantage against Phantoms and Interceptors, but a generally lower maneuverability advantage and less responsiveness. The advantages it could bring were real, but sometimes hard to make use of. The increase in restrictive terrain opens up a place for Defenders to operate. An HLC armed Delta is in the same points ballpark as a well-equipped Soontir Fel or Darth Vader, or a cheapish Whisper. It provides a firepower increase compared to all three, particularly if actions are taken away. It also has a substantial durability advantage to the others if Stress has been added, and actually has a greater maneuverability advantage under stress thanks to the white K-turn. The named pilots can further this advantage with action-less EPTs such as Predator and Lone Wolf. Vessery's pilot ability also fulfills this need. These EPTs are borderline irresponsible on Whisper or Soontir Fel, and although they are good on Vader, his actionless offense is quite low even with EPTs.
I'm not trying to say that Defenders will be the new go-to small ships for Imperial Squads, there's still lots of ways to argue that the big 3 Imperial pilots are better than Defenders in many ways. There is, however, a more defined set of advantages for these ships.