Are they substantial enough for motorcycling? The website has people skating half-pipes and such. The kevlar coverage looks decent though. What are your thoughts?
You are indeed correct with your observations, as from what I've read the guy who designed them, road motorbikes but also skated/bmx, and wanted a Kevlar lined jeans which the 'cool hipster skater kids' could wear without restricting leg movement. As you can see on from the pictures, the Kevlar appears to be as thick as Draggins I tried on in shop.
I have nothing against Draggin jeans or any other manufacture of Kevlar jeans for that matter. I personally wanted a skinny fit jean that could be worn as a dress pant, and the draggin's I tried on could not offer that, as I have a slim build (62kg /137 lbs, 180cm / 5f11 Tall). I also don't see the point in wear 'baggy' or 'too loose' fitting kevlar jeans, as in a crash the jeans will simply ride up, exposing skin.