This is a sounding board before possibly using contacting Fandom directly with this idea.
I would like to see .xml added to the list of approved file types to upload. Only admin can import files, at least on all the wikis here except the one where I am an admin. Because of that, it would be nice to give editors the ability to upload the .xml files they have exported from other wikis.
I do not think wiki admins want their editors to just copy and paste articles from one wiki to another. That is akin to stealing, since the editors of the original article do not get proper credit for it on the second or even third wiki.
I do not want my editors to steal articles, templates, images, basically anything from other wikis. I want them to properly export them and give them to me to import, after I looked them over.
There is a way. Go to special:export and choose the original source of the page. This would allow you to take the history outside. Then import it. However, you have to ensure that the pages line up or imported history will be at the wrong spot. That is no biggie since admins can change the history by deletion moving, and restoring.