You could call the faces in Fallout 3 and New Vegas ugly, and they might still be ugly, but the odd color tinting you'll see on NPCs, usually dark-skinned NPCs, is now muted. Mostly fixed, you might say. Works for player characters as well. First, credit to this thread over at the TTW forums for the information about EGT files.

Why shouldn't I use the files linked in the thread? It comes down to a matter of opinion, but the edited EGT files provided there end up loosing too much of the detail present in the original facegen textures. It doesn't look bad, but a little too bare for my taste. With my EGT edits, I tried to take a middle ground between the ugly colors and detail. The downside is not all of the ugliness is corrected, but it is much better than it was originally. And it will not apply to the player character.

Disclaimer: Body facegen textures are now a single color, and have to be, otherwise neckseams regardless of textures are worse. A whole new body and EGTs tuned to it could solve this, but well, that's beyond any scope I know. If you have any ideas, please let me know, or not. You don't have to. If you decide to tackle it on your own, good luck. It isn't fun.

Other mods to check out:
Two Wastelands Redesigned
TTW NPC Overhaul

The files included in the download cover the vanilla game plus the DLCs, with base game faces (no mods). And if you're on TTW, the same applies. If you want the changes to apply to NPCs with faces edited by mods, or new NPCs entirely, you'll need to download the optional file with the EGTs and generate facegen in the GECK. Or you could check out the mods I linked.

You need JIP for the BSAs to work properly. You can extract the BSA if you wish, but you're on your own if you do.

The optional file is my edited EGTs for use with the GECK.