Bacchus, I think you're a bit off mark with this one.

I just watched the video, and he doesn't fade out into the next song once as far as I saw. He's mixing the tunes, leaving them in and then dropping the outgoing tune as the incoming tunes breaks and drops the next bassline. You can see him mixing quite clearly in the video, so your viewpoint seems a little bizarre to me. I think I saw him drop mix once, which takes a lot of skill to do well anyway - and he most certainly does it well.

I'm not a fan of Promo, in fact this is the first time i've seen or heard him, and he seems highly skilled to me. Near every mix is spot on, the only one I could really hear that didn't quite work as he expected was at the 23 min mark, where a tune ends 32 beats earlier than he thought, but he still makes it sound pretty decent still. He mixes extremely fast too, which increases the chance of mistakes but I don't think I heard a single beat out in the whole set.