Have they changed how subscriptions work? I added the subscription option to one of my Gigs and have had three or four people order with it. When I have completed the first part of it, I don't see them again until the next month and then it looks like they drop into an "Incomplete" status waiting for the buyer's response. Are you suggesting these "incomplete" could hurt ranking? I actually have a non-subscription order that has been sitting that way for a couple of weeks now.
Honestly, I have been thinking about turning the feature off because it doesn't work the way I need it to. I would like to have more control over the subscription terms. It would be nice if I could set the quantity and the frequency. So instead of offering 1 per month, I could offer 2/month, 1/week, or even 3/week. Yes, I could set milestones, but you can't for jobs that don't meet the $50 threshold.