I find that doubtful. Spacecraft are typically structured to contain pressure rather than resist it.
I don't know if this is reference to what i wrote above, but:
1. I didn't write anything about ships generally being submersibles. Only being able to swim.
2. Actually our ships are structured to resist pressure. Any spaceship only structured to contain pressure would crack in seconds when being shot at, while many of the ships we fly can take a lot of beating before having problems.
Despite all of that, no, most would not make good submersibles. Even if your hull can take some pressure, there indeed not only is a limit to that, but also thrusters would run into problems quite soon. The Moray Starboat again comes to mind as -the- exception. According to Elite lore, it's a ship which is suitable for aquatic and submersed operation.
Also, are you suggesting that some of the ships are light enough to float in the atmosphere? That makes no sense. If there is gravity acting against any mass at all, it will reach the surface.
It's an interesting theory you state there. If you are right there, then this one can not exist:
https://en.wikipedia.org/wiki/Airship
Because that's what several ships in ED would actually be: airships. A great example is the Anaconda. It rivals the volume of a 100.000 tons aircraft carrier, while having 400 tons hull mass. (The Anaconda is more than half as long as the USS Nimitz, while being a good deal wider and higher than its hull. )
Even a fully outfitted Anaconda, with plenty of HRPs, is much lighter than the the ship should be if it would be all filled with helium, let alone something as heavy as air.
None of this is of consequence, however. I stand by my original point that the value of having a flying sub is virtually nul compared to the required programming and mechanics that would have to be executed. I think it's going to be hard enough for them to pull this off if they really are working on landing on ELW's. I suspect they'll have to just establish that there's a limited variety of "life" on planets, similar to what we're seeing with some of the stellar phenomena.
Depends. I actually think that putting in some submersed gameplay would be the easier first step. Procedure generated life forms are easier done in aquatic form than in land based form. We're much more ready to accept strangely shaped beings that swim, than those which clearly have lacking anatomy for moving on land. At the same time, the whole "now your ship is a submarine" or "now you deploy a submarine and move around under water with a similar movement model as in space" would add plenty of exploration area.
I see potential in both on atmospheric planets and in water exploration. Either would be fine for me and i wouldn't dismiss either as the possible next step of which kinds of planets we can explore.