I take it you haven't read many of the stories then.
I was just reading some. And, Conan wore armor just as any warrior would. When he didn't, it was because it was his earlier stories when he was broke or in his later stories because he was taken captive.
Have you read the Scarlet Citadel? Conan is a king. He's taken captive and loses his armor. Sure enough, he shows up in armor later... Hmmm.
Amalrus cried out in unbelief.
"I see Trocero and his captain Prospero--but who rides between them?"
"Ishtar preserve us!" shrieked Strabonus, paling. "It is King Conan!"
"You are mad!" squalled Tsotha, starting convulsively. "Conan has been in Satha's belly for days!" He stopped short, glaring wildly at the host which was dropping down, file by file, into the plain. He could not mistake the giant figure in black, gilt-worked armor on the great black stallion, riding beneath the billowing silken folds of the great banner. A scream of feline fury burst from Tsotha's lips, flecking his beard with foam. For the first time in his life, Strabonus saw the wizard completely upset, and shrank from the sight.
"Here is sorcery!" screamed Tsotha, clawing madly at his beard. "How could he have escaped and reached his kingdom in time to return with an army so quickly? This is the work of Pelias, curse him! I feel his hand in this! May I be cursed for not killing him when I had the power!"
The kings gaped at the mention of a man they believed ten years dead, and panic, emanating from the leaders, shook the host. All recognized the rider on the black stallion. Tsotha felt the superstitious dread of his men, and fury made a hellish mask of his face.
A few chapters later, Howard writes about how heavier armor is superior...
They were far outnumbered, and the Shemitish bow had the longer range, but in accuracy the Bossonians were equal to their foes, and they balanced sheer skill in archery by superiority in morale, and in excellency of armor. Within good range they loosed, and the Shemites went down by whole ranks. The blue-bearded warriors in their light mail shirts could not endure punishment as could the heavier-armored Bossonians. They broke, throwing away their bows, and their flight disordered the ranks of the Kothian spearmen behind them.
So, we're talking about replicating "genre vs. physics" and you cite Conan as an example where armor is meaningless in terms of survival because of "genre", yet here in this Conan story, Howard gives specific examples of better armor indicating a fighting unit's value.
And, Conan, well, he doesn't show up to the battle naked. No. He's wearing armor. Why? Because he's a king and he can afford it. And, of course heavier armor is better protection in a battle. And, the only reason you'd go into one wearing only a loin cloth is because you had to.
Want to emulate genre? Take away the PCs' stuff (capture them, steal from them, have stuff break, etc). Let their 14th level Fighters get out of situations with naught but a loin cloth and a rusty nail. That's genre emulation (and something later editions of D&D screwed up by making armor a "must have" because of the scaling of the math...).
But, making armor meaningless is not emulating anything... Neither physics or genre. It just doesn't make sense. Period.