Please consider the following scenario.
Create a recurring order with first order discounted (say 1st order FREE).
1. Create a recurring product.
2. Create a discount coupon and set maximum number of usage to 1 time per customer and assign it to the product.
3. Place the order, discount is applied to the order. So far so good.
4. For next cycle, it just replicates everything including discount coupon, although maximum number of times discount coupon can be used is 1
4. While placing order for recurring cycle, validate the discount coupon and apply it only if it's allowed.
I hope I'm not missing anything that's already there.