Wiki should autosave drafts
Some time ago, I tried to modify Jambi article to have more up to date information, but got busy with other things and continued it at later time.
When I finished it, and saved it, it seemed not to do anything, just displayed the old page.
While this is most likely some security feature or maybe even bug caused by conflictions, this kind of things would be recoverable if the system would save drafts automatically from the data you have edited. Too often I get distracted and get my browser killed or whatever... :) I suppose I’m not even only one with this kind of problems.
And just one more suggestion related to it. Notification about article changes if there were any between editing start and submitting.
As a sample of a Wiki implementation that handles auto-saving and session retrieval perfectly, have a look at Atlassian's Confluence.