As of the time I am writing this, lStewieAl's Tweaks and Engine Fixes has recently added the option "Sneaking Doesn't Force Power Attacks", which disables sneaking from forcing you to only do power attacks with melee weapons. While this works fine for the most part, this feature isn't exactly bug-free as it becomes an utterly broken mess once Fist weapons and Fists are involved.

"Why?" you may ask?

Simply put, there are no such animations made for this in the base game, thus the engine will try to use animations from the next most similar/relevant animation group and proceed to implode on itself.

"But wait a minute, why does it work for knives and sledgehammers then? There also aren't any sneak attack animations made for-"

It's a quirk of the Gamebryo Engine, do not question Todd Howard and his magnificence.

I initially brought attention to this issue by notifying Stewie, and they informed me that they would try to have a set of animations made or remove the feature entirely. While I did not like the prospect of having this feature removed, it was a safe assumption that a niche set of 3rd Person Unarmed/Fist Weapon Sneak Attack animations was not exactly the utmost priority of any animator in the FNV modding community by any means.

So I jury-rigged and cobbled together a fix myself, the best way my smooth brain knew how. And as an idiot savant's luck would have it, it seemed to work.

Installation: Drag and drop into the Data folder as per usual. Also requires the option enabled in lStewie's Tweaks (bSneakingDoesntForcePowerAttacks = 1)

Known Issues: The vast majority of unarmed (i.e. fists/brass knuckles, not power/ballistic fists) power attacks in 3rd Person will be Silent, Supersonic Falcon Punches. This appears mostly to be a visual glitch and as far as I can tell the power attack is still functionally the same. I don't know how to fix it, part of me doesn't care, at the very least this is better than the animated abomination that came before.