Fetch quest? What? Are you saying that, say, Flags of our Foul-Ups was a fetch quest? Crazy, Crazy, Crazy? Beyond the Beef? Restoring Hope? One for My Baby? For Auld Lang Syne? Eyesight to the Blind? I Forgot to Remember to Forget? The Whitewash? How about the Helios 1 quest? Or the Vault 11 quest? Raul's companion quest? Cass' companion quest?
Eyesight to the Blind and Crazy, Crazy, Crazy are essentially the same quest, and if you've done the latter before the former it just becomes, like many of the game's quests, an exercise in trudging to the designated destination to push the required button. Anyway, I'm talking about quests like: Sunshine Boogie; Young Hearts; Still In The Dark; Cold, Cold Heart; I Hear You Knocking; Debt Collector; Wang Dang Atomic Tango; Aba Daba Honeymoon; Don't Make A Beggar Out Of Me; Cry Me A River; Bitter Springs Infirmary Blues; No, Not Much; Return To Sender; Talent Pool [etcetera and so on]. Quests that consist of little more than "go talk to this bloke" or "deliver/collect this package".
In FO3, I had comic-book adventures. In NV, all too often I am an errand boy tasked to deliver messages and pull levers rather than doing anything exciting or fun.
(Booted, though not a fetch quest that was the one that stuck in the craw most. There are unmarked quests with more to them, when a quest title proudly flashes up on screen I expect events to take more than two minutes and to offer some kind of reward, even if it's just a thank-you.)
As for the "good quest design", the quests are good because they have options rather than linearity. Compare, say, the Replicated Man to Beyond the Beef. TRM had three options - you could cancel the quest early by giving Zimmer the fake android part, you could tell Zimmer that Harkness was the android, or you could unlock Harkness' robot memories. Of those, only the last two gave you worthwhile rewards. In BtB you can save Ted or not. If you choose to save him, there are at least three ways to do it that rely upon your character build, not counting shooting your way out of the WGS. You can also offer up one of your human companions as a meal instead with the [cannibal] perk.
And TRM was pretty much the pinnacle of good Bethesdan quest design, with an anemic three options, only two of those being worthwhile.
Non-linearity is admirable, but too often in NV it comes at the expense of robustness; so many of the more interesting quests in the game (most of which you have rightly mentioned) are incredibly fragile and easy to break, leaving you bogged down in savegame management and reaching for the walkthroughs. Beyond The Beef is a case in point, I had to reload about a dozen times between the kitchen and the dining room because the game had decided it didn't like the way I'd done things, or because important characters weren't doing what they were supposed to be doing (*cough*Mortimer*cough). Quest-essential npcs will disappear because they were spoken to at the wrong time, or never appear in the first place, or refuse to acknowledge the package you've brought them, or insist you killed their kith and kin when you did no such thing, and in the end I find myself yearning for a straightforward romp of a quest that doesn't break when you breathe on it.
I salute Obsidian's ambition, but I can't help but think it's also their downfall, and think a desire to have both more quests and more complex quests left them caught between two stools somewhat. I'd rather see fewer, better quests and less "go kill some scorpions mister/go back the way you came to deliver this message" filler quests. Or at least, make them unmarked quests, don't give them fully-fledged quest status. And for goodness' sake stop sending me back to dungeons I've already cleared out, Vault 22's pretty cool at first but the novelty wears off when you're being sent back there for Mcguffin after sodding Mcguffin.
So you're telling me that Fallout 3's zany what if scenario quests are better than Fallout New Vegas's more realistic quests?
Yes! If I want realistic dogsbody-drudgery and choredom I can find it in real life. I have a real job, I'm not after a virtual one.