There are two approaches,
real-time lighting
pre-baked lighting
Most action games' level design is set to a fix time. That enables the option for pre-baked lighting calculations to create more convincing lighting than real-time solutions. But that advantage is realized recently.
http://www.illuminatelabs.com/
This is good way of doing things. I do respect Crysis developers for pursuing real-time a lot, but for any other fix timed leveled game, pre-baked lighting solutions should become a standard.
Spherical harmonics, HDR lighting is on the way as well as real-time global illumination solutions. Right now there is a power, and software for that power. But I can see no games around utilizing those. It has been 2 years after Crysis. I really want to see something tops that. Being the next big engine/game, I expect these or more from id tech 5/Rage.
So it is not necessarily about 'other games', but it would be cool to know if a TES game would be possible. But what I saw from the video, it is a small level with canyons where you can't go over the hills because there is nothing to show there. With Megatexture, first thing I want to see is how it applies to outdoors like in TES games. If game world will still be that closed, the tech seems to be wasted, IMO. But I think it is not, and that level is small because they want to show how fast they can do things, the emphasis is at the fast. I'm asking this, because this is a game not a movie: Players want to go explore every inch of your map. And boundaries are not welcome as well as discovering a non-textured area.

More questions about Megatexture:
So is it working on statics too? Can a level designer stamp a building with it that easy?
The virtual world is showing hundreds of GBs of texture. But it is virtual. Is there a limit for original texture package? Or is it essentially, how much can you store on one DVD or 2?
Adding more custom textures on the way, is it possible and easy? Modders can do that?
Will there be a market for texture artist for id tech 5? Separation of bucket texturer and level painter? Because it truly industrializes the progress for texture artists, even inventing new jobs.