I think that's fairly common to be more in love with the first thing you tried. IME, I had played Fallout 1 and 2 as they released. Was exited for 3 when it came out, and while I thought it was a great game, it didn't feel like Fallout. New Vegas feels like the Fallout I know. 4 even feels like a good representation, though not as deep.
But I might feel as you do if I first played 3. Then all the other Fallout games would feel weird. lol
I have some opinions about 4, but nothing like the vitriol you feel towards it lol. Could I get an example of some things they removed in your opinion?
My complaints mostly boil down to how mediocre the story, world, and characters are. But I can't think of anything they removed necessarily, just poorly implemented