Maybe more random encounters can be added in the NV DLC that take place in the entire world, not just DLC.
Here are some of the one's from F3. If they added as many to NV, the world would be less bland. I'd feel like exploring again.
http://fallout.wikia.com/wiki/Fallout_3_random_encounters
:wacko: Wow, had no idea there were that many. I think I've only ever gotten half of those within a +200 hour playtime.
Vegas still has some random encounters like the hitsquads for pissing of either the Legion or the NCR or the random freeside thug attacks. Other then that though I don't think there are that much more.