A fixed blade without a sheath is a letter opener.
That said, David, especially in the ABS, the knives themselves are what should be judged. Sheaths are definitely a part of the package, but show very little about a person's understanding of squishing metal, which is what the ABS is rightfully concerned with.
I really prefer that a good sheath comes with a good knife, but I cannot fault a maker for a lack of leatherworking skills. Some have it, some don't does not make them any less of a knifemaker.
Can't stand Kydex for a forged blade, in most cases. My feeling is if the maker does not do adequate leatherwork, a sheath from a decent professional leather worker should be provided. In this we are talking about how that affects the final cost, and is not a reflection of the knifemakers skills.
Nick Wheeler made me a sheath for my Jelly Roll Fighter, and it is as much of a work of art as the knife itself. Don Fogg provided a sheath for the Clouds Bowie that I purchased, and it is VERY basic, and does not do the knife justice. Does that mean that Nick is great, and Don sucks?
Obviously, the answer is heck no. Just for the sake of argument, Ed Fowler makes a very serviceable sheath, but the style leaves me flat as a pancake, and if I owned one of his knives, I would have a "dress" Rowe sheath made for it. Just my .02. YMMV.
Best Regards,
STeven Garsson