My memory could also be being fuzzy. Might have been more like Oblivion and Skyrim.
As for the megatexture thing, it's not done anymore because it's not needed. The reason they had to have textures load back in was because the 360/PS3 only had 512MB of total RAM, and while the 360 had shared RAM, the PS3 had two 256MB sticks for the the CPU and GPU respectively. Nowadays even the Xbox 1 is rocking 8GB.