These are about 1/2 the weight of the Canyoneer II's.
As for rocks, they are a lot like a climbing shoe where its somewhat flexible and you can wrap the sole around rocks to get better grip. On Canyoneers, my feet couldn't flex the shoe, it would just be the mid sole compressing around the rock. I always thought the felt like a beefy hiking boot. The other week on a pinned boat with the water tennies, I was on a quite pointy rock and my feet and the shoe bent about 90 degrees around the rock for grip. That sole/mid sole was thick enough to disperse the point of the rock (I could have never stood on that rock yanking on a boat barefoot without ripping up my foot), but the wrapping effect gave me better grip. I don't think the rubber in the sole is going to give out on pointy rocks or anything. I say that because I'm almost 100% sure the rubber is what I have on my FiveTen Downhill mt. bike shoes which pretty much make you feel like your clipped in on platforms. They have a very different, much thicker mid sole like the Canyoneers, but the rubber was worn exceptionally well for being on 20 screws all day long. I've had that pair of shoes for 3 seasons now on 20-pin pedals and the sole still hasn't worn through.
One change I just made on my Water Tennies, I added a Sole insole. I have super high arches, so most shoes do not have very high arch support, so that added just a little stiffness and support. I tried to add these in the Canyoneers and they just didn't have the right volume to work for my foot, so I had to stay with the standard insoles.