To be honest, I think a lot of my problems with New Vegas is that its wasteland is mostly mapped out, and that you are dealing with large groups in a rebuilt world instead of doing the rebuilding and mapping out yourself. I think Fallout 3 is the best game of all time percisely because it put so much of its work into a fusion of exploration and choice, and I think that the world of Fallout fits them a lot better than a medieval fantasy world.
I guess what I mean, is that in New Vegas and TES, you already know whats ahead of you, for the most part. There is a central government that patrols the roads, and either by reading it in books in previous games or by having a long conversation with someone in the starter town, you have a good idea of what to expect from the world map. In Fallout 3, you discover the goings on of the wasteland by witnessing it yourself, you figure out that the super mutants are kind of a big deal when you blunder into them going into DC, you see that the Enclave is mysteriously watching the wasteland by taking a look at the eyebot in Springvale.
Even then, I think that the true thing that made Fallout 3 great was less the overarching storyline, and more the immediate exploration and choices. My vision for Fallout 4 is to be able to wander through the wasteland, crest a hill, come across a community with very unique circumstances, characteristics, and way of looking at things, and then make a massive impact on that communities history by your actions only to dissapear into the wastes as you crest the next hill. That, alongside picking through ruins of the old world for both supplies and small stories about the old world itself, is what I think New Vegas really lacked in a lot of places.
New Vegas is still a great game though, and in Honest Hearts I basically see what I described. From learning about the tribes of the land after a hard journey through danger, to finding pieces of a world once forgotten with the survivalist, and making a grand impact on that community that will reverberate through generations, only to wander out of the sight of their history and end up doing it all again when you find a different land.