New Vegas world has a two-fold punch. First, it's set in the Mojave, which is already a wasteland. Fallout just added a bunch of radiation and mutants to it.

Second of you came to the series with the first two, it's like coming home. The world makes the story, and is an integral part of it.

It's that lack of a setting that fits that hurts F3. A story about the importance of water works marvelously in a desert. Not so much in a lush, wetland. (Or rather it can, but needs to be told differently.)

As for Fallout 4... I don't hate it, but it lacked things I liked a out of the box.

And if you like it, but don't want to build them your self, use Sim Settlements. Let's you automate the process.