I liked Fallout 3 more for the same reasons as you, but I don't think it's because New Vegas was the worse game. In fact, I think NV was better.

I (and I'm guessing you) enjoyed FO3 more because it was all new to me. I didn't know what to expect, how to survive. I wasn't playing the game as much as experiencing it one encounter at a time.

It was my first Bethesda game. I thought VATS was only used as a shooting tutorial in the vault and didn't know it could be used in the real game. I didn't know there was a map; I certainly didn't know about fast travel. I murdered the first ghoul I saw wearing clothing outside Undercity because I didn't know nonferals existed. I later hid it's body so I wasn't found out. I thought Greyditch was this Megaton I was supposed to find, but it SUCKED and was full of ants. It was the first place I went after leaving 101. Using an unrepaired combat knife, a few grenades, and meticulous save reloading, I killed all the ants and their queen. You could jump on top of them, spin in place, and stab downward without getting hit by their fire attack.

I just had no idea what I was doing and I loved it - after leaving Greyditch, at least. I was trapped there for about the first week I had the game.

By NV, I knew how the system worked. I knew what VATS was, how to use the map. I knew how the radar worked. Not only that, because of my absolute ineptitude in Fallout 3, I became good at surviving.

So in NV some cool stuff happened, some fun stuff happened, but in the end it was just a game. A game I now knew how to beat. I'm guessing that something similar happened with you, though probably not as pitifully stupid.