Hrunting, Sting, Anduril, Excalibur, Grayswandir, Green Destiny... magic weapons in fantasy fiction are unique items with a history. In D&D, magic weapons tend to be generic types. This irks me, especially when having a +1 longsword by the time you're second level is pretty standard in most campaigns.
Honestly, how many lost magic swords do you think should be floating around in a campaign to await discovery? I bet I could keep player interest if they knew that there were no more than half a dozen truly magical blades in the world that had been lost, and no more... and that only one or two smiths in the world knew how to make such weapons.
I'm hardly the first to suggest that RPGs are too generous in this regard, with their gross deflation in the value and scarcity of magic weapons. But how would you actually make this work in-game?
My thoughts follow after the break...
There are plenty of reasons why a sword might be +1 or better without resort to magic.
For the same reasons that a Les Paul is easier to play than Fender Squire, some weapons are mundane, but superior. Better balance, use of high-grade steel, robust construction -- you can drop plenty of these into your mix of party loot without making truly magic weapons seem ho-hum. The important thing is that being a better swordsman should unlock more of the weapon's potential, like a fine instrument in the hands of a master musician. These weapons won't make much difference to a raw recruit, but to a veteran swordsman, they could provide significant advantage. I model this in Dungeonteller by allowing superior weapons to add one or more Muscle dice to your die roll but never more Muscle dice than you have Battle dice. This way, even very fine weapons don't do all that much for a weak fighter, but can significantly improve the damage dealt by a skilled fighter.
A class feature of the warrior could be the ability to recognize the maker's mark and lineage of such superior weapons.
"The crossed hammers on the blade show this is dwarf-make, and the signature rune identifies the smith as Exalted Master Ironbones, who was active about three centuries ago, during the Deep Wars." Now you've got a weapon you're going to cherish, even if it's not strictly magical.
Truly Magic Weapons are Rare, Famous, and Coveted. And they have a provenance.
If you spend any amount of time in the taverns and guard rooms of Stormgate, you'll hear stories of legendary lost blades, like Black Shard, Rognar's Razor, and Touch of Fate. Or Flenser, the mighty falchion made by the blind smith Olm Dalgaar for his beloved queen, Camia War-maker. Buried with Camia, the blade was too coveted to lie in the earth unclaimed for long, and within 20 years, turned up in the hands of a corsair captain on the Emerald Coast. It's said that before his surrender to the Imperial Navy, the corsair hid the sword somewhere on his ship, hoping to return to revover it, but the vessel was scuttled by his crew and now Flenser is said to lie in 20 fathoms of water somewhere near Cape Fare-thee-Ill.
Magic Weapons can do something cool besides provide bonuses to attack and damage.
Flenser, for example, shrieks and whistles when flourished in the air, causing its enemies to shrink in fear. The infamous dagger Black Shard creates wounds that can't be closed without divine aid. And so on. As often as possible, I try not to resort to standard bennies like flaming or frost unless it compliments the weapon's provenance.