On the topic of "limited" or "rare" items -- what if you didn't intuitively know an item was rare? Video games color code items based on their "rarity." Lately, games also outright divulge the drop rate of particular desired items/heroes, instead of leaving it to the studious community to piece together.
One definition of rarity:
"(of a thing) not found in large numbers and consequently of interest or value."
What if the item you find isn't marked with keywords (Common, Uncommon, Rare, Legendary) or colors to indicate it is rare - but it is the first of it's kind you've found in 5 weeks of playing and it has an interesting property you find desirable? How much would you sell it for? How much would someone buy it for? Have you ever seen this item in the marketplace before? Are you the first to find one? Without it being marked as Legendary (yellow font color) how do you know how much it is worth?
From a user perspective, it is important to know you have something valuable on your hands so you don't accidentally toss it or vendor it as a new or inexperienced player. Color-coded items are more user-friendly. Yet also very rigid.
"Not found in large numbers" implies that only so many are available. As someone else in this thread pointed out: grindable items will be harvested in mass quantities at the cost of time spent, no matter how "rarely" they drop. But if there is a limited quantity of an item that can exist at any given time... that is truly rare. It won't drop again until some other copy of it has been destroyed or sitting idle in storage for x months.
For an item to be "Legendary" is less about its quantity in existence and more about its history. Legendary ought to mean there are legends behind it that make it so desirable. A great hero wearing it in an epic battle. A horrible fiend using it for a devastating ritual. A goddess blessing it with divine energy to protect the prince some thousand years ago. Or, a skillful player -- the first to wield it in a century -- slaying x number of enemies (or other players) with it. Forever memorialized in the item's flavor text for all to know should they too stumble upon the weapon.
