I think a good etching design definitely does look better, but as to whether it adds to the blade....I think that's more a preference of the buyer. In general I would try to stick with a etching design that's as professional as your knife design. I really like the way T mickley etches his knives that I have seen. Simple name on one side with the metal type on the opposite side.
For me personally I like a small makers mark that doesn't take anything away from the beauty of the blade, but I don't really need the steel type on the blade. I know it can help down the road in identification, but if I bought the knife I know what steel it is so it's not a big deal to me....I agree with Keith every custom knife should come with some sort of certificate of authenticity.