We usually run a couple of link-ups at a time. For example, we're doing a link party where people post giveaways on their own blog and then come to link up on our site. We have one link-up for people willing to ship internationally, and another for US only. People post in the wrong link-up all the time. As an admin it would be great to move them from one to the other. As it is we have to delete and ask them to recreate the link. Not super difficult, but it would cut out a couple of steps of communication and hassle.
We would really appreciate this one too. We have several open linkups at the same time and people make mistakes that would be much easier and faster to solve if we could just move the links. And also sometimes links apply to two different linkups at the same time and it would be awesome to be able to just "duplicate" existing links in the second linkup.