My mistake. I looked back at the thread and the conclusion was that the firespray survives one more attack than the defender. It was the B-wing comparison in that same thread that mixed me up.
As for interceptors, I just looked again at the lists of top cuts from regionals, and I didn't see many (if any) hull upgrades, so not sure what you meant there. There were plenty of elite PTL, with an occasional variation of SD or TC, and or Alphas with nothing.
I'm not saying a defender is an auto include by any means, but I think it has more potential to be competitive than people are giving it credit for.
They have potential, but I'd rather have a Firespray any day of the week. The rear arc and access to crew outweighs the base size significantly.