i think the most difference is not the 2d/3d, it is the game rules.
in FO2, you must be very cautious, a small group of enclave solider kill low level player certainly, even you have 1000 Super Stimpak.
in FO3, nothing you need to worry, all you need is just Stimpak. "give me 1000 stimpak, i can defeat behemoth with my bare hand in level 1".
FO2 is RPG, FO3 is shooting game, that's my point.

And my point will be that this has been said over and over again. At least, search for the most recent thread to post your opinion in.

Though I think the last one reached its post limit.

Umm, no. While the difficulty level in FO3 seems lower than it is in FO2 (even at Very Difficult) part of that is due to the smoother save and reload feature.
Beating a Behemoth at Level 1 would require a console cheat (as you are Level 2 as soon as you exit the Vault) so yes, if you are using console cheats - you can easily "beat a Behemoth at Level 1" (God mode anyone?) And while I agree that the Stimpack mechanic in FO3 is a bit broken - 1000 Stimpacks? Who has 1000 stimpacks? That's like... um... just no.

Still, major things that made F2 hardcoe are missing. You mentioned Enclave patrol ? Yep, 10mm Pistol vs. Advanced Power Amor = Your death.
While in F3 the damage threshold is missing and you can bare-fist an enclave goon to death(Tried that, it's a fact xD!).

Topics discussing game differences belong in the Fallout series forum. Moving it there.

Sure. In FO2, you could always run into a random encounter that gave the Player two options - Run or Die. I don't know whay that makes FO2 more of an RPG and FO3 more of a shooter. In fact, in FO3, you can start your character wandering off as soon as you exit the vault, and if he survives all the Raiders, Yao Gaoi, Super Mutants and Giant Radscorpions along the way, he's still faced with "Run od Die" once he gets to .

But I seriously believe that the reason FO3 seems so "easy" is the painless-ness of Save and Load. Seriously, keep track of how often your character dies - for me it is a heck of a lot.

Also, that damage threshold worked both ways - that's one of the reasons why people were fast tracking to get the power armor early in the game. Seriously, Level 3 and in PA? Kinda silly, and unbalanced.

But, still I have to agree that the whole Stimpack mechanism in FO3 is broken. There's no cost (other than using up a Stimpack) to using a Stimpack. No cooldown, no temporary effects like the screen shaking (wheee, I'm over stimulated!!!) or that weird "chem effect" with the funny sound and visuals. Apparently drinking a beer will have a bigger effect on you than popping half a dozen stimpacks. There isn't even the risk of addiction (which would be totally awesome since Stimpacks don't "wear off" so the effects would be always on. I would have made it "You can't sleep. And you find that stimpacks don't have the kick they once had {restore fewer HP}.").

i find a MOD changing Stimpak to generate health instead of instant effect, since not perfect, i think it's still a good solution.

just compare the game system to FO2, FO3 is too "simple" for RPG, maybe we can call it "RPG-besed adventure-style shooting-game"...