I kinda feel that NV is less about "exploring" and more about "interacting" in general. There's a big difference in the design intention. I don't feel that NV was ever designed as a game where you just wander aimlessly and explore random or unmarked locations and get rewarded with cool shit. There is some of that, but it's rare and not really part of the core game design scope.
More importantly NV is designed as a game which is designed such that there's a lot for the player to interact with, and the various locations, including non-essential locations, are usually linked up or related to some sort of quest or reference made while interacting with something in the world. There's a real sense of the entire world being living and populated by various people and factions. Even in non-essential locations, there is often some sort of tiny bit of story/lore element which ties it with the world. There are signs of people who have visited areas before, and either left behind signs of their passage through the area, or did not survive their entry/residence in that place.
Such design is very subtle, and much more interesting in terms of world building, compared to simply making lots of "cool" stuff which reward the player in terms of raw game-isms (phat loot, epic encounters, etc). When exploring in New Vegas, it is often not very fun to just wander the wasteland aimlessly looking for "cool shit" because you'll probably never find any. On the other hand, if your exploration is objective in nature, and it involves finding new settlements, or talking to as many people as you can in a given area and following up on things they mentioned or doing every side quest offered, you can find a lot of rewarding stuff often hidden in mundane areas.
Even by following up on faction quests, and gaining enough favor to actually join a faction, will reward you with a safehouse key, faction armor, and possibly other faction related goodies which I feel really enhances the roleplaying experience. By helping the Followers of the Apocalypse enough, and being able to join them officially, not only do you get the coat in a legit manner, but you also get to buy mags from Fawkes, and you get a safehouse key. In the safehouse, you find pretty decent loot available on the beds as a reward for your membership, and there's even a Follower who drops by in the safehouse from time to time, creating a sense that it is being maintained by someone.
There's nothing in NV which hits you over the head with "ZOMG LOOK AT THIS, IT'S SO COOL!!!!!", but I also don't think that is the only sort of design philosophy which should exist. NV isn't the sort of game where you fight a giant Radscorpion boss the size of Godzilla which breaks out of a ruined skyscraper and starts eating NCR troops. It's the sort of game where someone will tell you a story of how there's a giant Radscorpion the size of Godzilla wandering around and sometimes feasts on patrolling NCR troops, and then you call the guy the liar. Because he is.