My first play through of Vegas clocked in at over 200 hours and finished it 2 times after. The role playing felt very vague, the biggest consequence I had on all playthroughs combined was accidentally blowing up up the NCR base in the beginning and having the odd group tracking me down every now and again. More choices and outcomes than Fallout 1 or 2? I suggest you play those or if you have, again, there were sometimes 4 or 5 ways of completing a quest. 95% of the 'choices' in New Vegas have the same outcome in any case. Most are illusion. Not a good RPG, it's a average shooter with a fun story and has better writing than Bethesturd games.
I assure you I've played 1, 2 and NV to the point of exhaustion. 3 as well, actually, because my pain threshold is high.
It seems like you're overstating how much reactivity Fallout has and understating how much NV has. Since I have some time to kill, let's take some Fallout quests:
-Save Tandi - basically has two outcomes. You peacefully get Tandi back (3 ways to do this, 4 if you include the ghost thing), or you kill everyone.
-Save Shitty Sands from scorpions - One outcome, two ways to do it (blow them up or shoot them). No lasting effect on the game, as far as I remember, other than curing the dude of scorp poisoning.
-The entire Junktown quest - Two outcomes (help Gizmo or help Killian), neither of which really get acknowledged by the game (everyone talking about how scared they are of Gizmo when he's been dead for weeks). There's 4 ways to do it that I can think of - kill Killian, kill Gizmo, talk to Killian and then kill Gizmo, or refuse to help and get put in jail.
-Find out what happened to the missing caravans. Only one outcome (you find out about the mutants and meet the deathclaw), and only one way to do it (talk to Harold, kill the Deathclaw). No lasting effect on the game.
-Save the slaves from the raiders. Only one outcome and one way to get it - kill everyone.
-Clear the dude's farm of raiders. One outcome, one way to do it. No lasting effect on the game.
-Stop the Skulz. Three outcomes (they end up dead, they end up in jail, or you join them), four ways I can think of to do it.
-Get the Water Chip from Necropolis. Two outcomes (fix the pump or don't), two ways to do it.
-The Cathedral and Mariposa, both of which are probably the best parts of the game. Only one outcome (not counting joining the mutants), but about a trillion ways to get there.
-Join the BoS. One way to do it.
Let's take some NV quests. Note that almost everything has a lasting impact, however minor, thanks to the reputation system:
-Goodsprings. Two outcomes (help the town or help the Powder Gangers), two ways to reach it, with one of those ways featuring a wealth of dialogue skill-checks to give you items and allies. Has a lasting effect if you kill the Powder Ganger leader yourself, as your reputation deteriorates to the point where you'll be ambushed on the way to Primm. Also, the questgiver can die in the battle, which means you can't get your reward and you miss an encounter with him later on.
-Beyond the Beef. Four outcomes that I can think of, a ridiculous amount of ways to reach them. No lasting effect on the game, unless you turn the White Gloves into cannibals and then side with Mr House.
-Boulder City. Three outcomes (Khans leave peacefully, Khans die, Khans escape violently), five ways to achieve them, and the bonus element of two hostages who can live or die depending on your actions. No lasting effect except reputation boost/loss with NCR and Khans.
-Come Fly With Me (i hate this fucking quest). Three outcomes (the rockets launch, the rockets blow up, or you kill everyone), three ways to do it.
-Great Khans. Three outcomes (Papa is leader, someone else is leader, or you kill everyone), a bunch of ways to get them:
http://fallout.wikia.com/wiki/Oh_My_Papa Has a lasting effect and changes the final quest.
-The White Wash. This is another pretty complex one, so I'll just link the wiki article:
http://fallout.wikia.com/wiki/The_White_Wash If you expand the quick walkthrough, it lists a lot of the available routes and outcomes.
-The entire main quest.
-GI Blues. Two outcomes (one of which is a bad ending which you can easily achieve by mistake, which I think is a good thing), a bunch of ways to get them with a lot of speech checks on the way.
If it seems like I'm cherry-picking, feel free to check out any NV quest and any Fallout quest at random on the Fallout wiki and compare them.