I wonder at what point, if ever, Bethesda will take a step back and agree it's time for a completely new engine... like they did back when they started working on Morrowind. I mean, it's not that big of a deal, now. Many engines carry traces of code from the engines they descended from... such as how you'll find a lot of Carmack's own coding in plenty of engines that supposedly branched off years ago. However, there will come a point when having remnants of Morrowind's coding in Bethesda's engine just won't be good enough, I imagine. It's only been 9 years, so that time isn't quite now, certainly, and after extensively modifying the engine as they just did, I imagine they'll use it for at least one more game, so perhaps for a Fallout 4 on the next console generation... but then what?
When they move to next gen.
For a game with the interactivity and, well, sheer amount of things to do, and on a 360, I certainly am not complaining. Given the choice of a modified Gamebryo, with a few unwanted 'artefacts', but the ability to interact with insects and pick up every knife and fork, or a truly beautiful world, where interaction with the scenery is limited to chests that glow, it's a no-brainer. Creation looks more than good enough considering the depth of character - world interactivity. A few graphical oddities, like a clear view down througgh the water, or the rain under shelters, might upset some, but I am sure I will be fine with it.