We should be able to define if/then statements for promotions for order criteria (ie IF a customer orders this specific shirt + this specific jacket THEN this will happen. This could be useful for 'grouped product' promotions and all sorts of other clever stuff.)
We should be able to limit coupons to a specific color of a specific item if we want. Go nuts with specificity here.
There should be custom messages to the customer when a coupon is applied/when it fails to apply about criteria for that offer being met/not being met. These should be store-owner defined on a per coupon/promo basis.
There should be a way to auto-apply a coupon/promotion based a specific URL or query string (ie customer clicks on 20% off _______ PPC/Email/Social ad, and that pricing discount is automatically applied to their session for that item (or whatever items are included in the promotion) while keeping the regular list pricing the same for other visitors)