When I say rarity, I mean in the sense of diabo or other RPG's, where "rarity" isn't how often you find an item, but a class of item. Common, uncommon, rare, epic, legendary, mythical Each class up has the potential to drop with more enhancements than the last, making a mythical item . . . not necessarily better than a mere rare, but those drops carry much more potential.
Thus, you could have a projectile cannon, then a rare projectile cannon with bonuses to various stats (Bonuses other than upgrades it may come with,) and a mythical with six different various upgrades, that, if you're really lucky, work together synergistically.
BS:H doesn't seem to be built on this model, which is why I said that it didn't seem to have any place here.
Honestly, the rare (as in, not often seen) weapons in BS:H are so damn rare, that I actually felt quite scandalized to discover that my energy cannon - one of the cheapest things I could make - outperformed celestial ion weapons and gatling energy cannons in combat. You only get these from asteroids, and most asteroids drop junk.
