Rather than giving weapons and armor direct ratings that simply add or reduce damage, I think it would be more fun to play with the dice themselves. There are several abilities that replace the default fate dice with different colored dice that have special effects. The effect have a rating that specify how many dice are replaced, e.g. Accurate:2 replace 2 dice with accurate dice. You may have multiple types of substitutions on a single roll, e.g. Accurate:1, Powerful:1. You may not have more that 4 dice substitutions in a single roll.
If you roll a minus [-] on an accurate dice, it is counted as a blank [ ] instead.
If you roll a plus [+] on a powerful dice, you gain another shift of effect if your roll is successful.
If you roll a minus [-] on an uncertain dice, something bad and unexpected happens. You opposition gains a boost against you.
Instead of rolling a Fudge dice, Legendary dice are a D4 that is directly added to the result.