So, how would a Sharpe’s Tower of the Elephant have turned out?

Intriguingly, if you dropped the Richard Sharpe into Howard’s scenario, he’d do pretty well. Where Conan is a (duh!) barbarian, Sharpe is a survivor of the gutter. Both are fearsome fighters. If the Cimmerian is probably the stronger, the rifleman has a rifle (duh!).
Sharpe would’ve shot the 1st thief from long range. Got over the wall no problem. Hacked down the lion with his heavy saber…. And so on.
As a role-playing game this would be fun. However, as a story… strangely unsatisfying, because the substitution buggers the structure, and so beggars the theme.
If you read
my earlier post, I hope I convinced you that Howard’s “Tower of the Elephant” works structurally because the all the pop-up-fall-over characters represent aspects of civilized humanity. Conan, representing barbarism, is either in conflict or competition with them. So even though the story is built of episodes, it has one big running conflict to drive it – Barbarism vs Civilisation.
Sharpe is an urban thief turned soldier. He might be an even match for Conan, but he’s actually a product of civilization; if he steps up to the adventure, the main running conflict simply collapses. What’s left is a shallow caper story. Cool, but not really memorable.
It happens in fiction as well, unsubtly in tie-in and posthumous continuations, and subtly where novelists seek to emulate what they don’t understand (much like the wannabes in Castiligone’s story who ape a great general’s squint, not realizing that it is in fact a congenital defect).
Good, emotionally resonant adventure stories are not mere chronicles. Theme, protagonist and scenario form a self supporting triangle. If just one of these does not fit the whole, then you’re left with a meaningless squiggle.