sounds painful to balance but it should be a case where its one positive and a negative e.g. -2 strength but + 2 finesse on plate armor
I agree for having both of positive and negatives "stats" but
-2 strength +2 finesse is kinda in the same way of the existing item (enven if it's better than nothing yeah).
I see it more like "you critical strikes stun" and -10% to total damages, or "each time your deal a critical strike you heal for 10% of your max health" but have -4 all principal damaging attributes (strength intel finesse).
