Li, I tend to agree that a host of minor magical items gets boring quickly. I run a homebrew campaign and design all of my own adventures, so I tend to place fewer, more interesting treasures than those indicated by general guidelines. When the players defeat NPC's, they'll often get the NPC gear, which usually consists of more minor items, but placed treasures are rarer.
To those who feel that each magic item needs individual history, I disagree. IMHO, in a world where there are thousands of 5th level fighters (mercenaries, soldiers-of-fortune, adventurers, personal guards, etc.), there will be thousands of +1 swords. Sure, each one has a history, but do you really care that Bob the mercenary finally saved enough gold to purchase an enchanted sword, which he fought with for several years before coming to his demise fighting orcs on the Great Wastes, and that's why the orc war-chief had it?
It seems to me that the biggest problem is that the description of the swords is very generic and unimaginative. It would seem much less artificial if "+1" swords were known as something more descriptive. Even something as simple as "battle-hardened" for +1 and "supreme" for +5 would go a long way. Instead of having a +1 sword, you have a "battle-hardened sword". Instead of having a +5 sword, you have a "supreme sword."