Not a boffin,
I'm curious why you think an LHD is 'far from flexible'? To my mind a boat that's only slightly bigger than a CVS that has 1000+ grunts on board, a platoon of tanks, a bunch of LARs, artillery + a stack of hummers + CH53s, Cobras, Hueys and AV8Bs might in some way be a bit more flexible than the mighty CVF that can.... launch F-35s. During OIF the LHD I was on carried 1500 odd grunts to the beaches, then reconfigured to 'Harrier carrier' and operated 24 Harriers for the duration and we didn't scrape the surface of the armouries on board. But you're right in one thing - the accommodation isn't salubrious. They are built to be warships though, not cruise liners/cocktail party venues.
I don't know for sure, but I'd hope the new LHX would be even better? If shipyard jobs weren't an issue, we could probably afford half a dozen for the price of the CVF programme.
Single Seat, Single Engine, The Only Way To Fly