I know about the current workarounds. Please do not close this discussion until the desired solution is here.
You've given us the ability to stack coupons. What you've done, if I understand correctly, is allow the customer to enter multiple coupon codes on a single order... thus, stack them. What we need is the ability to offer a coupon that applies a discount AND tick a free shipping option in the code so the single coupon code does both. Also, we should be able to select whether free shipping applies to the entire order or just the discounted item.