Bad example because they made the fairly bizarre decision to have party time mentats, egregious even amongst the general background radiation of poorly designed buff-tedium
FNV was mass-market and probably self-consciously designed not to prevent you from making the PC into Bethesdaman, able to do anything in a single playthrough and pass any stat check or combat by stacking thousands of console inventory-fucking buffs while studiously avoiding any sense of character or personhood in favor of being a pure cipher.
I never came across party time mentats once in my non-meta gaming playthrough. The wiki says they're sold in one place in the entire game, which belongs to a faction allied with Caesar's Legion(Which is probably the least played faction, and has very little benefits overall). Only available after passing a science check.(Or craftable for the same check and ingredients.)
Even then, what does that help really? Gives you a minute of having tougher companions, or passing a speech check of 30 when your speech is only 20? But I agree that it could have been done better, however, consider it an improvement from what it was built on. Obsidian said that part of making a sequel is living up to fan expectations, which in this case were mostly a bunch of frothing consoletard FO3 fans. They don't have that weighing them down this time.
Bethesda-man is not possible with vanilla FNV, with every single DLC, yes. But every DLC added more perks, so you'll never be a true bethesda man.(Anyone see Skyrim's latest patch? They decided that having 2/3rds of the perks in the game was stupid, so they took off the level/perk cap indefinitely, lol.)
Unless a later patch fixed things, damage threshold in New Vegas was terribly implemented. Because there was one universal stat for damage threshold (unlike Fallout 1/2, which had multiple ones for different types of damage), it greatly favored weapons with a higher damage-per-shot and punished the use of automatic weaponry, especially in the late game where everyone and their brother had high DT.
And the silly workaround of adding a certain percentage of the damage to "bleed through" hardly helped automatic weapons stay relevant while eliminating one of the most satisfying results of a damage threshold mechanic; feeling like a tank when in high-level armor. No longer could your Vault-Dweller Courier strike a Superman pose against raiders armed with nothing but rifles, impervious to all (but a freak critical) in his power armor.
This is what the different ammo types were for, match ammo negated extra DT and added more damage, AP negated lots of DT for a damage decrease, increasing viability of these weapons. Besides that, there was the BAR rifle with damage equal to most non automatic weapons, and the LMG itself was fairly high damage. All weapons that used 5mm rounds(Minigun, assault carbine) had a -5 DT, -10 for match, and -(Really big number) for AP rounds. Cazadores, Legionaries, great khans, geckos, mutants, centaurs, yaoi guai, mantises, all have low enough DT for a LMG to be effective against. It's also a bit logical don't you think? Why should shooting a bunch of tiny bullets at armour they can't pierce do lots of damage?