Enable users to withdraw their own Feature Requests and Bug Reports
I've submitted a lot of RFEs. Some are very popular, others have been massively downvoted. A couple have been duplicates. I'd be quite happy to withdraw the downvoted ones and duplicates and save the team the time of reading through requests that clearly aren't going to happen. Also I'd feel a lot better about reforming and re-proposing a different approach if I didn't already have an open request that's waiting to be rejected.
Also I've submitted at least one bug that turned out not to be a bug. I could have withdrawn that too. :)