You may not have been in need of a pep-talk, heck I mean nobody is, what you feel about anything is completely up to you. But time has certainly changed the opinions of many people re both films - many who dismissed both films in 1979 and 1982 later revised their opinions radically, but for a time it could have been argued that both films were bombs, Alien critically and BR financially (and critically in much of the world, though not all). Nobody would argue this today. KR's thesis that Prometheus may become a classic seems a stretch to me, too, right now. But it may.
I've yet to see Robin Hood...not sure I should, lol. I did read the story of the script, a sad one to be sure.
Yes, I noted your initial remarks were more luke-warm than vitriolic. My expectations going in were so low that they could not fail to be exceeded - to steal your food analogy I expected to be given a piece of stale mouldy cheese and received a fresh, hot Big Mac instead. Not sure if that helps explain my pass mark for the film overall, but it may have something to do with it.
Strength, weight, mass, they're all separate things as you quite rightly point out. We would naturally tend to assume it is more dense than foam or balsa, but perhaps that isn't a safe thing to do. The noses of the Jockey biosuit helmets seem to have a cellular construction, for example. So I'd concede you have a point, but it only goes so far. The volume difference is enormous; to make the big one out of the same mass it'd have to be spread very, very thin - balloon thin, almost. Or if cellular, each cell would have to be even thinner.
What did you think of my medical nutrients idea...does that seem feasible?