Uninstalling Flow creates this problem
"There are log entries for the existing Flow posts in people's contributions, and other logs. With the pages deleted and disabled with the kill switch, those entries will be red links, and if you click on one of those links, you'll get a message saying that it's been deleted. If the extension was completely uninstalled, then there's no software that recognizes what those links are, so clicking on them would cause a, and attempting to undelete them could cause a serious error."
I think this is bad for any wiki -- Wikimedia wiki or any ordinary wiki that tries to use Flow. Flow needs to have an uninstallation script that handles possible serious errors.