How can we improve WHMCS?

The API allows only to read existing promotional coupons. Would be nice to deactivate a coupon used (when it allows only 1 use), or reduce the number of times a coupon can be used. For example, in the case of single coupon use, we want to remove or disable used coupons to avoid 2nd use. In a case a coupon is allowed to be used 100 times, we would like to reduce the count with each signup to 99, 98, 97 as orders come in, and to block the coupon when all 100 allowed activations are completed.