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By reducing the magical enchantment of all weapons, high power weapons become less frequent. The +4 Warblade in Ribalds would now be +2, all the +3 weapons become +1, all the +2 weapons become normal weapons etc.
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How about making the +2 weapons into Masterwork weapons? You'd get +1 to hit, no damage bonus, and it doesn't count as a magical weapon.
That way, they'd still be worth finding, but not especially powerful.