What I've noticed is that there are several places were the world geometry is sloppy made. Some places you can slip under and enter inside cliffs/rocky outcrops and so on. Sometimes it can cause players to get stuck, or make the fall out of the world altogether! The last happened to me when I was in sneakmode in the Dead Money DLC. I fell through the floor and slid right to the bottom of the world geometry. It was in the quest of triggering the gala here; http://www.youtube.com/watch?v=c6oCo_q0BkY&NR=1 at approximately 9 minutes: 13 seconds into this walkthrough. So, I'm not sure who checks the world geometry is ok, but they're not doing their job.

I have found so many of these probably more than i lot of people something like 50 places all over the map. some even cause you to drop through the world and some make your game crash but for some reason save the game before you crash making it very frustrationg.

I noticed quite a few places where there are holes in the mojave wasteland proper, didn't find any in dead money though so I guess i'm lucky. As for not doing their job, you have to remember that they have a lot of things on their minds while world building, and they're busy quick-checking the map to make sure there aren't any huge problems that they might not see every nook and cranney. It's not about mismanagement, it's rushing to get it done on-time.
Yeah there's alot of places with these, but maybe they worked out a few in the next update

In a game this huge, some minor issues like this should be expected. Particularly when working with the crappy engine they have.

Fallout 3 had them too, after all.