WPEngine disables post revisions to improve performance (revisions are saved in the database and it can lead to lots of cruft over time). See http://wpengine.com/support/i-noticed-revisions-are-disabled-why-also-how-do-i-enable-them/ However, being able to revert to a previous version of a post can be invaluable, especially on sites like Hacks where multiple authors and editors collaborate on posts before they're published. Sometimes a glitch happens while saving a post and some content is lost (character encoding or malformed HTML are the usual suspects). Without a previous revision to restore that content might be gone forever. We would like to reenable revisions for blog.mozilla.org with a limit of 3 revisions saved. We should work with WPEngine support to get this done. If it's at all possible it might be nice to enable revisions only for the Hacks blog (which probably needs it most) but I'm not sure if there's a way to enable revisions for only certain blogs in a multisite network.
Craig, with the access you have now, you should be able to open a support ticket with them :) You'll be able to explain this way better than I can for example.
Craig, Is this still an issue?
Timeout, re-open if this is needed and we can work with WPEngine to figure out impact and see if we can get this going.