Cord and leather wrappings on European swords and knives? Hell! Wire wrapping is the most commonly found surface on the blades meant for battle, secured on one side by a big honk'n pommel, and on the other with a sizable crossgaurd. Even most of the using Rapiers, as opposed to court swords, I've seen are wire wrapped. Well done wire wrapping holds up a lot better than well done cord and silk or even leather wrapping. And makes for a very secure grip.
I do not know what the "flow" you speak of is. It's not the same as the "combative flow", that it from technique to technique. Flow is well understood in the West, and indeed an integral part of those arts. Maybe you speak of a more "spiritual flow", I know that the Eastern arts place more emphasis on spirituality than the Western arts. The only guy I know who got into that was Saviolo, but only in a limited sense.
Oh, as a point of fact, I've seen katanas with the rayskin exposed. The amount and style varied with the status of the individual. I'd reckon with intended use too. Any sword that's gonna see heavy combat is gonna get REAL bloody, and all that cloth wrapping is gonna get gross. I know, I once used a cord wrapped Ek in one of my primitive hunts. Yuck! Now, a small blade=bloody blade, and a sword has some length, but a sword does more killing for longer periods. Also, even the best cloth wrapping starts coming undone with heavy and hard use.
I gotta back up Cougar hear, checkering, texturing, is a plus, not a detriment.