It's hard to make a comparison between ET:QW and Crysis because they're not meant to be played like that...
From the sky? No, but like I said any air vehicles or large variations in height will make these issues stick out like a sore thumb. I only picked out a birds eye shot to compare it easier to another birds eye shot. I'm not comparing gameplay at all, either, I'm just comparing engines, so I think the comparisons between Crysis and ETQW/id Tech 5 are fine for this purpose, although Crysis multiplayer works a bit like BF's multiplayer from what I tried in the beta.
I'd assume if a game based on more conventional texturing techniques was released and was designed to be played from a height the issue wouldn't be as prevalent, if at all.
Most RTSes use the same method of rendering terrain: heightmaps and vertex blending. Arguably, RTSes stand to gain the most from this kind of technology.
Unique texturing allows a lot more details like the erosion channels, the sand dunes, and generally goes a far way to making areas look unique-- provided the artists are up to it. You could create a blown up chunk of road WITHOUT having to make it a separate texture, and make all the variations for it if required, and all the material references just for a one-off usage.
it's just not as radical as Carmack would like to have us believe
Why not? There is no game on the market on any platform today that can use unique texturing on any surface, or gives artists the equivalent freedom that unique texturing provides. I would even go so far as saying there aren't any freeware games, indie games, open source projects that use this technology, but I'm not 100% sure about that.
It is radical in that this is a first for PC gaming, and that it radically alters the workflow of development. Check out the QuakeCon video from last year about the tools if you haven't watched it.
Is it as radical for gamers? Probably not, but Carmack is an engine programmer. He's speaking about engines, and he generally doesn't dumb down or is concerned about what the end-user wants to hear about. You generally don't have engine programmers giving interviews as often as Carmack does, which probably doesn't help the situation much.