Suppose we declared that no no-artifact weapon (or implement for 4E gamers) has an attack/damage bonus of more than +1? In fact, assume the same thing for armor and other defense-boosting items. None of them any more than +1. They can have special abilities beyond this +1, but it's all conditianlly useful stuiff like flaming swords and 1/Encounter Dispel magic power usage and stuff like that. Let's also assume that the DM has "fixed the math" by either messing with the monster stats or giving PCs free inherent bonuses as they level up.
What are the consequences for that?
On the plus side:
The first magic weapon your PC finds might well be the one that he keeps, essentially unchanged, for the rest of the game. Yet at the same time, it's easier to use 'break the weapon' and 'steal the weapons' type attacks and plots without harming the PC all that much. You're never doing them out of more than a +1 and a conditionally useful power.
It frees up money. PCs aren't going to feel the need to save their treasure for upgrading or buyingmagic items. Oh, some of them still might for the bags of holding and thunder stones and stuff like that, but there's not nearly as much pressure. They're more likely to spend treasure on buying a fortress or a title of nobility or whatever in-game roleplaying stuff there might be to do with cash. If you run a treasure-light game, that's all right too.
On the negative side:
It encourages the "golf bag of weapons". There's little reason for eveybody not to be carrying around five or six of the best weapons/implements they can find and pulling out the most useful one for any occasion.
Don't have the thrill of cosntantly seeking upgrades.
Plenty of money for rituals (but is that such a big deal?)