I have noticed in official guides and wikis that Argonians have a damage bonus because of their tough scaly skin, but in Skyrim, they hit with their claws like Khajiit, why is that? And why not give them the additional 12 damage bonus if they do so? And why do Khajiit have 10 base damage instead of 4?
Also, the Daedric Gauntlets end in really sharp, ebony claws forged by Daedra; but the animation remains the same as "true" unarmed combat and there is no bonus damage. (same goes for Stormcloak Officer Bracers and Vampire Gauntlets)

TL;DR? Why unarmed Argonians =/= unarmed Khajiit?

Is this a feature or a developer oversight? And is there a mod that fixes it?

Just one of the many features that couldn't get in the party because of time restriction.

Argonians to more base damage then any other race except Khajiit.

I know
But why not as much/more as/than Khajiit? Since they have scales and claws?

Have you ever seen the biceps on a pride leader male lion? There's your answer.

I love unarmed combat. It's so cool when you do a sneak attack with heavy armor gauntlets and snap the person's back and neck.