I think it would be beneficial to be able to see the changes you've made to a wiki via Special:ManageWiki prior to submitting them. This would be useful for a couple of reasons:

• To check if you accidentally pressed a checkbox you didn't mean to press
• To review your changes in case you forgot which settings you changed

I'm imagining the listed changes appear on the "Submit" tab above the "Reason" field. It could take various forms:

• Similar to how Special:Log?type=managewiki it might just say something like "You're changing the following settings: ext-flow, ext-twocolconflict, ext-visualeditor, setting-wgDefaultSkin"
• Or a slightly more involved UI, it might do something like this:
  • You're changing the following settings:
    • ext-flow was toggled on
    • ext-twocolconflict was toggled off
    • ext-visualeditor was toggled on
    • setting-wgDefaultSkin was changed from vector to timeless
• Or something else entirely.

Obviously, the exact phrasing is up for changing.