Maybe that's misleading. Countess and Vessery are still in the mid-20s at Metawing, and Delta/Glaive both come in in the 60s (with Maarek Stele a surprising 40ish). Ship type looks 14th or so, and 4th among Imperials, after TAP, SF, and Advanced.
Maybe folks just stopped talking about Defenders. But it felt like folks stopped flying them for a while. Were they that bad against Fairship Rebels?
I just did very well at Escalation (4-0) with a bunch of /x7 Defenders (and Palp in rounds 3/4), and they just felt so strong. A lot is luck (Defenders are certainly a ship which has a high luck upside), but I didn't lose a Defender until the 4th round facing 150 points of heavy Rebel stress and ion control. Predictable, sure, but they've got a lot going for them. Free evades, white K-turns, and enough dice to potentially thwart alpha strikes seem to be strong enough to power through predictability.