That's largely due to the fact that Bethesda's worlds are full of dynamic and random encounters along with a constantly updating map, whereas NV was something more like Morrowind were 99% of the NPCs just stand in one spot all day.
NV never had anything like the enclave outposts and vertibird encounters in Fallout 3, or how the various factions in Fallout 4 start actualyl setting up outposts, sending squads on recon/purge missions, etc. etc.
Even Sawyer has said he wishes he could go back and add those sort of things to NV.
New Vegas had no consequences outside its ending slides... which is to say none at all. All New Vegas did in-game was the same thing Fallout 4 does, replace one group of generic NPCs with a named NPC leader with a group of generic NPCs and maybe a named leader from the other faction. And Fallout 4 easily trumps NV in that regard with its far more active BoS vertibird assaults and synth spawns. Nothing you did actually mattered in the game itself in NV.
As for dialogue... "I KNOW HOW TO USE DYNAMITE!" and "I TOLD THEM HAD A THEORETICAL DEGREE IN PHYSICS" are hardly great lines. NV's dialogue was as good as every other game, which is too say, utter [censored].
And I wold rather have game with few options then one with a bunch where none of them actually DO anything. There was more of an actual change in the game world from the USS Constitute quest then there was in 90% of the quests in New Vegas. Options mean nothing unless those options actually DO something in the game itself, and changing ending slides isn't in the game itself.
Well Fallout 3's world, as has been demonstrated times beyond counting, was never like that.... so Fallout 4 is really no different there.