Link-only answers shouldn't get an automatic delete vote. If they should, then this could be scripted. When you go to /review the note under Low Quality Posts says "Identify, then improve or delete low-quality posts." You always have the option to improve the post by clicking 'Edit' instead of delete.
In addition to that, when reviewing a post you're also shown how many other answers are on that question and whether or not the currently reviewed answer is accepted or not. Even if an answer is link-only, I think we should just leave them alone (or edit them, but don't delete them) if they're the only answer or the accepted answer. You don't have to edit these yourself, but I usually leave a comment asking the OP to improve them.
While this may theoretically answer the question, it would be preferable to include the essential parts of the answer here, and provide the link for reference.
Note that this only applies if the link hasn't rotted yet. If the link is already broken, go ahead and flag for immediate deletion. Moderators can leave a comment asking the OP to fix up their post while it's in the deleted state, then they can flag it again once it's fixed.