Board Thread:Online Discussion/@comment-180.95.18.10-20130528000937/@comment-4224668-20130601052837

My best guess is Bethesda's tech skills keep improving. I mean, the character models never look the same because they have yet to publish two games on the same platform (excluding PC, but they update so often that it's hard to call a Windows 98 the same as a Windows 8).

There could also be different artists doing the concept work.