It seems to me that the term "re-hash" is used to mean "re-use"... Like re-using the Stimpak model, or the deathclaw model, or even a tricycle model... Is it really "re-hashing" to use a model that looks like what you are depicting? I mean... if the game has deathclaws, they should make new models that look like something else? If not, they should completely rebuild the deathclaw model from scratch and have it look like the one that exists already? I don't understand the common lament of "Its just a rehash of FO3

". The games share some assets; the games have some of the same "mass produced items", and creatures in them; I don't see how this is a problem. :shrug:
As for exploration... I would have a problem with a game that purports a 200 year span of time in which various old shacks were at no time looted by any of a few thousand explorers looking for salvage... To have an abandoned house in ANY town with a stocked first aid kit, or a mini-nuke in the closet ~or weapon of any kind but a lead pipe... unforgivably ridiculous. That was Fallout 3, this is not. Players that recall the landscape of Fallout recall that nearly everything was looted decades before 'you' got there (as it should be).
So many demanded 'realism' and 'immersion' of the world, then choked at the first taste of what that means. FO:NV (what I've seen of it) is a lot more realistic than FO3. When you find a shack out in the open, you should expect that 50 people have scoured it recently, and not be disappointed that there is nothing in it if you decide to look too; and to be really surprised and upbeat about finding something they didn't ~which usually shouldn't happen (and shouldn't be obvious). Also, some places are just places; a playground might be just a playground, and doesn't have to have a grenade hidden somewhere for the player to find.
IMO it doesn't make it a waste, or lazy to not have hidden goodies stuffed in every conceivable nook and cranny of anything that stands out on the landscape. Its just as true to say, "Whats the point of exploring when I can get everything I will ever need off..." of the ground and shelves of any building in any direction. When every place in the game has some form of reward hidden away in it, the rewards themselves become stale and taken for granted. Isn't it better that some are hidden well enough not to be found by a cursory glance, and not common enough to warrant a thorough search of every location ~and so, go undiscovered until after many play-throughs and a bit of chance... This way the game can still surprise you after a few months (or years).
IMO exploring is its own reward (and the only reward that should be offered from every location in the game). Finding cool stuff is great, but its even better when its plausible.
I have bought 3 unique weapons off merchants so far, like I said you can get everything you need from merchants.
This would seem to make the most sense no? Merchants are likely the ones scouring for salvage, and just might have acquired a thing that was looted days or weeks before, from a place you explored afterward. :shrug: