No matter how easy it is to revert changes, it is always possible a change will be missed when using a public contribution system. Not to mention, even if they are reverted, any changes made ontop of them will be reverted as well, even if they were good. The only way to prevent losing changes that were placed ontop is to go onto the page and manually delete what that edit added which is a lot of effort. As I said, it's a lot to keep track of when done through a fully public format.
And most importantly, I would rather not put Lore pages at risk of vandalization at all, I am fully willing to read through a ginormous list of suggestions and approve them one by one if I have to, but I don't want a fully public contribution system, not so long as the Lore Devs and Wiki Maintainers share the wiki. If the Lore team post in support of a fully public system then I might change my mind on that. Until then, I'm sure that I would want a suggest and approval system. And if not a suggest and approval system, then at minimum a manual account creation system.
A solution to this would be to move every lore page to its own Lore namespace. Then create a usergroup, say `lore` that can only edit that namespace. See $wgNamespaceProtection and user rights. Alternatively, lock every lore page.