The B Word
Take out the large blimp that is too expensive to replace and the whole fleet loses its AEW capability with one low-tech attack.
Blinkered thinking I think. Why is it vulnerable? To what? Is it any more expensive than a single Merlin? How many Merlins do you need clattering around at 6, 7 or 8k vice one unmanned HAV at say 15 or 20k?