I have recently experienced just a little too much of this "invisible wall" crap in New Vegas. I don't know if it's walls or the navmesh, but I am really sick and tired of not being able to get over a bit of mountainous terrain like I could in FO3.
One excellent example is with the [censored] path behind the Great Khans that leads to the Cazador nest where you collect their eggs. I had to zig-zag and run around for about ten [censored] minutes before I could get up that thing. And it was just a ramp. Just a [censored] ramp! OF EARTH!!! And I couldn't [censored] climb it!!!
Enough raging. Breathe. In for five seconds. Hold for three. Out for five. Woo-sah. Calmness fills me now.
One more thing that could make New Vegas better for me is more reliable access to weapon mods. Which I've said before. A few times. In different threads. I'm sorry (actually, I'm not sorry, but whatever) but it just doesn't make a [censored] lick of sense that I go to the Gun Runners and they don't have a Hunting Rifle Scope. I shouldn't have to force their inventory to cycle. Gun Runners should ALWAYS have all Gun mods. (and, incidentally, BoS should ALWAYS have all the Energy Weapon mods).
I also happen to agree that random encounters would be great BUT only if the level cap gets removed. With random encounters I'd probably hit level 35 before I was even done with a quarter of the game's quests. See, when I get XP, I want it to COUNT (meaning, I want to eventually get a level from my XP gain) not fall off into a void; random encounters would result in a lot of XP eventually counting for nothing (falling into the XP void) because I'd have hit the level cap long before I could complete all the quests I like to complete.
I despair because we shall see none of these things.