I was thinking more along the lines of the rammers you see with a bunch of razors on the front and not much else. The weapons are still going to do amplified damage, even if they comply to the DSL no stacking rule.
Easy fix, make heavy weapon more efficient than light weapons.
A lot of the abuse now comes from Razor Tips and DS Light being Razor Tips and DS Light, while sledge hammer has crappy 300 dp and no additional efficiency. You make the hammer have 500 dp while retaining it's HP, and all of a sudden heavy weapon becomes a lot more appealing.