Small gameplay improvements aren't enough to make up for the massive retardation of the setting and plot. People love to bash Bethesda for ruining the Fallout world, but Black Isle did that themselves with the talking deathclaw furries, the meme vaults, and a town literally covered in shit. That garbage drags down the good stuff (New Reno, Vault City etc.).
Fallout 2 was decline.
Even New Reno had a lot of stupid stuff. You get to be a fluffer in a porn studio, but then you get poisoned from all the cum you guzzle. Did people play this game when they were 10 and find the jokes funny or something? You have sex with the wife of a crime boss, but it says you weren't good enough in bed so she falls asleep before telling you her secret. But hey, you can pick the sex perk and do a great job and she'll let you know! If Bethesda put any of this garbage in a game, they'd rightfully be pilloried. That video of Megaton that people like to put up is honestly less stupid than a lot of the stuff in Fallout 2.
"They both had pop culture references!" Yeah, one had a few Easter eggs, the other had you literally fighting Pinky and the Brain. To get to a shit bomb, so you can create an explosion that covers the town in shit.
Even the non-idiocy stuff is a step down. People talk about C&C, but a lot of the times people are fine with you helping out their enemies. You can tip off the NCR spy in Vault City, and the Vault City leaders don't care. You can do all but the final job for all the mob families. Take a bunch of jobs from family X to kill family Y, then immediately walk over to family Y and ask for a job and they're happy to have you on board.
And the design of the game is just poor in a lot of places. Combat in Fallout isn't good, but it can be fun in small doses. But adding a bunch of combat dungeons like Fallout 2 does just makes the game tedious.
I honestly doubt people grasp the quality of Fallout 1 when they claim Fallout 2 is of similar quality.