Basicly what Notch is saying is that they're marketing over the nice looks, making it breaking through and revolutionary and not communicating on the drawbacks (stockage space of the assets and other).
In his article he links to other projects and engines that already existed in 2008. Atomontage engine looks pretty impressive.
What I was wondering about is how Euclideon will include physic and apply it to each "grain of dirt" ^^
In atomontage the guy took the opposite way. He's built physic that was able to render. He's talking about matter, etc...
The video is impressive too, and 6 months old now ^^
So basicly, this will be a revolution for players when this will arrive to them. No matter who gives it away the first (Euclideon proving their point or anyone else just having worked really hard) and for how long tech-demos have existed.
I believe the guy is over-hyping it, and disappear again for a year ^^
Mostly marketing and raising funds. Other projects are really at work, so whatever.
But the fact is it is doable, it will become true. But it is probable that we will need to wait a few years, for the technology to be fully developped and the computer gear to have raised (the more power, the more render) before it becomes mainstream.
And in 20 to 30 years, there will be a Voxel based Construct.
"Wait and see"