Maybe I'm missing something, but I find it strange that I have to save my wiki edits (and thus commit a snapshot to history) in order to preview how my wiki page will look. Esp. when using Wiki blocks, you don't really know what the page is going to look like until you actually save it.
Being able to preview a wiki page before saving it would keep the page's history from getting cluttered up.
It's upset to see that preview feature is still now available yet. It should be very usefully to let author see the output before they saving it to avoid unnecessary useless commits. Or maybe I miss the tip of how to use it if it's been already out there?