Fair enough, but even accepting that, it never having been relevant to my experience does speak something about the weight mechanical abstractions like sneak attacks have in the overall experience.
In the nu-Fallouts my playstyle is consistently almost entirely based on sneak attack criticals to overcome huge HP pools on enemies that take up to a dozen headshots from a bolt action rifle otherwise, whereas in STALKER any of that is not something I've ever thought about. Shooting things in the head just kills them dead. Anything that won't go down in one clean shot feels more like a miniboss because of extra abilities. Dwarves with telekinesis and shields, controllers with their psychic blasts, pseudogiants with their everything...
The more openly stat-based approach of Fallout lends itself more to lazy solutions with NEW ENEMY CLASS, MORE HP AND DAMAGE.
And while I don't want to say either is inherently superior as a format, and both are obviously very technically troubled games, personally I find the relative opacity of STALKER's mechanics to lend it a more organic and substantial feel overall.
That, and the floaty and disconnected movement in Bethesda's Gamebryo iteration.