. Not As Many Things To Do As In Fallout 3
. Vaults Are Crappy Nothing Interesting
I just felt like I needed to respond to these 2, first for objective reasons, second for subjective ones.
1. This is factually untrue. Perhaps you spent more time with Fallout 3 running around the wasteland randomly because of higher spawn frequencies and more randomness, but that is basically just one thing to do in the game. You could very well do the same thing in New Vegas, you might just not find it as appealing. So really, the actual con would be "less rewarding exploration" or "less appealing exploration". Other than that, New Vegas simply has more to do than Fallout 3. More quests, more crafting options, more weapons, armors, etc. If you have a point to make that involves proving Fallout 3 has more to do than New Vegas beyond just walking around, I'd like to see it.
2. I must ask you A. Which vaults you visited and B. What Fallout 3 did better with vaults. Also, was it the experiments you thought were crappy and uninteresting? The content of the vaults? Loot? Here's a basic rundown of the vaults in-game (spoiler-free):
Vault 21: Doesn't really count, as it is mostly inaccessible and is no longer something one would explore. Still, has quests.
Vault 3: Quests are involved, non-hostile versions of a certain faction.
Vault 22: Quests, unique storyline (extends to DLCs)
Vault 34: Very rewarding, quests, lots of things that attack you
Vault 19: Quests and characters
Vault 11: Nothing obvious, takes some digging for it to be worth it
So just about all of them have something worthwhile in them, and most of them have quests involved with them. So I'm really, really flabbergasted that you'd say they were crappy and uninteresting, and I find it almost hard to believe that you've actually experienced all of the them before making your opinion.
OT (finally): I don't dislike New Vegas, and it is one of my favorite games. However, I do have some main complaints:
-Invisible walls. When they're not at the borders of the game, they are absolutely horrible.
-Dynamics. Things are just too static and they revolve too much around the player.
-Quest markers. Most quests give enough details that finding things should be trivial or at worst, force you to use your brain. Quest markers kind of ruin that fun when you know exactly where things will be as opposed to their approximate location.