I agree that wider tires are better for mixed surfaces, especially with a heavy load or a heavy rider (I'm
#225 ).
I ride a lot of gravel roads and paths which can have a loose surface where they've been recently re-done, as well as sandy spots, potholes, and washboard. My 650 x 38 Pari-Moto tires can make it, but still dig in dangerously in spots. My 26 x 60 Super Moto tires have a lot more float and just fly over all but the roughest loose gravel.
I also agree that you have to choose the correct Schwalbe tires. They make many variants of each tire design, varying in size, construction, bead, and puncture proofing. Their high-end, lightweight variants are legit race quality tires.
The Schwalbe Super Moto is already everything that Jan's new fat tires are trying to be. Fat, and fast.
They're expensive and hard to find in the states, though. I order them by the handful for $34 from Germany.
And yes, a rigid 26er mtb is can be roughly the same as the Ravn, but with weird geometry quirks. Or chainstay U-brakes.
Honestly, my experience with my converted '88 Schwinn KOM makes a modern bike like the Ravn more attractive. Simply because it is even more dialed-in for the type of riding I do.
But I would definitely prefer a bike like the Elephant NFE (or even Jones Plus) because of the disc brakes.