Telengard
Arcane
I'll take the bait.Nobody has yet put forward a compelling case as to why they believe NV is lacklustre yet (sorry NotAGolfer)...
Sure the Codex has likely had such discussions back on release but I think many people don't give it enough time or don't look hard enough.
GAMEPLAY
1) Doesn't like its own challenge. The game actually recommends against its own survivalism difficulty setting due it being too much of a "challenge".
2) Despite that, you have to mod in actual challenge on top of that setting for there to be any challenge (and needing mods to work is never a good start).
3) Hideously overpowered start. Have to ditch a WHOLE BUNCH of equipment gifted to you at the start (Ultimate Edition) for there to be any challenge.
4) The guns totally lack a sense of balance. Found a sniper rifle early on, and it was a wickedly powerful weapon even in melee combat. I'll stay that again, a sniper rifle was wickedly effective in melee combat. Never needed to change guns again, ever. For any reason. (There is a brief time when the power curve of the enemy exceeds the sniper rifle's damage, but the division is swiftly overcome by your stats/drugs, which soon begin boost criticalling everything.)
5) The guns totally lack a sense of realism. Running backwards and shooting things in the head with a sniper rifle is way too effective.
STORY
1) The courier lacked any motivation for 9/10 of what he did. Motivation is the central pivot around which a story revolves. Or doesn't, in this case.
2) The Legion was never established as a viable threat, especially after your started slaughtering entire villages of them by yourself. -Okay, Legion is poorly equipped but has huge advantage in numbers, against a well-armed opponent spread too thin. Fine. But the division actually on the ground is just plain silly. I mean, they could head down to the local machine gun/assault rifle/laser rifle/sniper rifle emporium and stock up on everything, then place the Courier and four other guys on a mountaintop overlooking the approach to the dam, and have the five of you slaughter the entire army of axe and acid sword wielding Legion army unchallenged. I mean, it's not like you didn't already murder/death/rape half their army while just wandering around the desert looking for revenge against someone not even involved in the Legion.
3) Revenge stories work as tight, linear, death-knell marches of murder and mayhem, not madcap romps across a wasteland meeting tons of zany characters and doing favors for them or mouthing off to them.
4) The world was empty where it should have been filled (settlements) and filled where it should have been empty (wilderness).
5) The entire affair was more of a Lone Ranger Western than an Apocalypse story, but as a Western, it lacked the central themes which drive a Western, since its central themes remained Fallout's core wasteland apocalypse themes. Leading to a mish mash of story that never really says anything about the world or its characters.
The writing was fine, but not really memorable. No one really stood out that you could hang your hat on, and only some of the locations really resonated. So, dull gunplay, mess of a story and theme, and writing that did the job, but no more (which is still so much better than FO3 that it isn't even funny). What NV has as its advantages is a huge CYOA extravaganza and the usual Bethesda inherited exploration. Stack all that together, and it all adds up to an overall lackluster experience. Unless, that is, you're in it for the exploration or CYOA. Then, it's an incredible experience.