Dear Mr. Bad Example,
I would love to have your knife and its sheath. And because I'm an economic animal, I would love to have it for the absolute lowest price.
However, I believe it's wrong to discount your otherwise mint knife because it has a couple of Kydex scratches. If you want a fixed blade tactical knife, it is probably going to have a Kydex sheath, not because Kydex is so beautiful--it's not beautiful at all--but because nothing else endures better than Kydex in the field.
It is perfectly legitmate to collect tactical knives. But tactical knives are not custom knives (well, not usually). Custom knife collectors set great store by the materials and workmanship of the handle. And, heck, some of them are so gorgeous you could just die. Many of those collectors insist that their knives been in flawless condition, and that's fine.
Tactical knife people are nearly the reverse. The handles of tactical knives are usually made of stock materials--G-10, Micarta, or paracord, not abalone or mammoth ivory. The blades, however, are another story.
Places like Strider, Busse, and Mad Dog create their own metallurgical recipes for the optimal blade. They focus on blade geometry and edge grind. These, to me, involve a different sort of aesthetics from handle aesthetics, but it is not only not less legitimate, you could make the case that it is purer: the soul of a knife is in the blade, not in the handle. Particularly a tactical knife.
Tactical knives come in Kydex sheaths because that pairing makes sense. Kydex will eventually scratch a knife blade. Yet a knife with Kydex scratches could still be, technically, mint, in the sense that it has never been used.
Such scratches may be anathema to collectors of custom knives with beautifully polished blades that could, in a pinch, cut something, but which, by virtue of their beauty, were not really meant to cut anything.
Tactical knives are not created to be collected. They are created to be used. Who cares if a tactical knife has Kydex scratches? Goes with the territory. With tactial knives, the whole thing rests on performance.
But because tactical knives aren't created to be collected, does this mean people shouldn't collect them? Of course not. But should those same people expect that semi-custom tactical knives be as beautiful as custom knives? No, they should not. It's apples and oranges.
If you seek the perfection of a knife with a beatuiful handle and a scarless blade, collect customs. If you seek the perfection of a knife with a beautiful blade designed from the ground up to perform flawlessly in life or death situations, Kydex scars on the blade do not spoil the knife's perfection. They are nothing.