Strongly disagree that it reaches New Vegas. The lack of so many crucial RPG elements (skills affecting dialog, multiple outcomes for most quests, protagonist that isn't force-fed, being the big ones) means it fails at being a good RPG and a good Fallout game to me. It is an enjoyable shooter with RPG elements, with better than average writing from Bethesda and some cool ideas and moments. I loved walking around in my X-01 Power Armor and all that. But I'm probably not going to ever finish the game a second time, while I did 4 full playthroughs of New Vegas, more than any game save Dragon Age: Origins. The replay value and interesting RPG opportunities just aren't there.
Some of the issues you cite I really don't consider issues, or question the degree of difference.
Skills affecting dialogue is a good one. I frankly detested the idea that you needed a perk to be interested in men, and a separate one for women- I enjoyed the options, but not the requirement of perks for a key point of roleplaying that shouldn't need perks. While I prefer the 'minimum requirements for 100% success' of FNV to the semi-random system of FO3 and FO4, I disliked how that system was tied to skill points rather than SPECIAL- charisma was a dump stat in most respects, because intelligence would give you more points to put into speach or barter.
In general across most medium, I have a skepticism of perks enabling speach options. Far too often they're merely the 'I win' button in a conversation, while the restrictions for not using them are... well, iffy at times. In Mass Effect, a lot of the Paragon/Renegade persuades were just saying the reasonable thing.
For multiple outcomes to resolving quests, that depends on where you look and what degree you want. FNV certainly had it's share of missions which essentially required combat in great gobs- it's not like every mission had a non-combat option or path. Nor is FO4 devoid of options to sneak, hack, or steal your way through a solution. I would agree that FNV did it better- especially with critical path quests- but it's a matter of degrees.
Opinions are opinions, so I'm not trying to tell you that you should enjoy FO4 more. But I think it's fair to say that FO4 does some things better than FNV- and considering how the game is largely built on those things, that's a fair thing to consider. If you can give a significant list of things FO4 does better, after enough things it's plausible to call it a rival.
My (personal) list of things FO4 does better than FNV- even if in some cases FNV never tried them at all
-Crafting and global economy
-Equipment customization
-Settlement development
-Companion relationships (companion stories are better in FNV, but romantic relationships actually have something there, compared to absence)
-Factional balance and co-equal development
-Villainous groups (characterization for raiders, good development of Institute)
-Pragmatic/subtle evil (less absurd/over-the-top evilisms)
-Better ambient music
-Improved combat
Now, there's a great other list of things I think FNV does better. Even a bigger list- I do thing FNV is ultimately the better game. But FO4 is no slouch, and makes an attempt at a number of things FNV didn't even try.
It IS better than FO3, sure. But it still has some bizzare design decisions. The awful dialog wheel is a big one. So is the ******-poor interface across the board. And why bother ditching Skills, when half the perk tree is just incremental bonuses to combat and crafting abilities, AKA the exact same thing Skills did in FO3 and NV?
That one's relatively easy- skill points were imbalanced and an impeditment to the balance of SPECIAL.
In FO3 and FNV, what really mattered was your skill points. Not only did this make Intelligence an over-powered stat (max-intel was the game-breaking special stat in most respects thanks to boosting all abilities via points), but FNV and FO3 both struggled with balancing the arrangement perks. FO3's perks were too powerful in many respects- after the early game you basically had all the battle-winning perks you wanted- while FNV's came had scarcity compared to a lot of options which, rather than all being equal, tended to make some the dominant selection paths.
As it was, perks and skill points had a functional overlap. FO3 removes the redundancy and focuses on making SPECIAL more relevant. And it is- not only are SPECIAL points themselves better balanced vis-a-v-is their usefulness, but they serve as better gates to perks than just skill point.