I will add my two cents here (a bit far from the original subject, yet connected in my opinion).
First of all, I fully agree with @Rivkin, who expressed the point far more clearly than I could have.
Secondly, there have always been both good and poor blades, regardless of the period. The finest swords were those best suited to their intended purpose. It therefore makes little sense to compare, for example, a Kamakura tachi with a Kanbun-period blade later modified to fit a sword cane in the Meiji period.
Today, we are far from those times of warfare, at least in their traditional form. I believe that we now collect swords primarily for their historical significance (of which all blades are a part), their aesthetic qualities, and, for some people, the prestige associated to the blade/the smith. Since the original functional aspect of the sword is no longer central, a wide range of blades from every era, regardless of sugata, hamon, or hada, whether signed or mumei, and whether associated with a prestigious lineage, a temple, or an ordinary samurai, can be appreciated on their own merits. I believe that every smiths probably created at least one piece that could be fully enjoyable !