We've struggled to get drag semantics right. What we have is powerful but not right enough to meet everyday authoring and refactoring needs.
Drag content between wikis should follow mac/windows convention. Makes a copy. Drag within a wiki does a move. ★
Only move items between origin pages or local pages. Everything else is a copy, including anything from ghost pages.
Drag a copy from template or ✔ revision.
Make recent-vistors a ghost page. Make ghost pages read only.
Drag within search results writes corrupted search-results page. See exception noted in Special Page Names.