This is a complete strange technique to me. It's still pretty new unknown. Just found out about it on Guitar Player.
http://www.youtube.com/watch?v=xqnSk1QQ550

This will be a great technique for neo-classical metal musicians.

Pretty neat. Sort of a variation on sweeping. It gives a pretty cool sound though I fear he may be limiting himself somewhat by only muting with his fretting hand.

The technique seems really inconvenient to me. Seems like it's essentially similar to sweeping, but produces a different, warmer tone; the downsides are too big.

First of all, the technique is limited to a number of shapes, which you can definitely hear in the guy's playing. That, and it seems to take him time to switch the position of his pick so that he can even perform it - going both up and down.

I think what you said about it could be fixed like Ibanez said about using the fretting hand more.
Since it is like tapping, you could hold down some frets and do it.

As for the switching, I bet if he practiced more with it. He'll eventually become quicker like how sweep picking evolved.

The guy came up with the technique in 1994. If he hasn't practiced it enough in 16 years, well...

It is quite funny. It took Joseph Kekuku 7 years to master the slide and this guy still haven't got faster at descending and ascending with his technique.