Basically, what I need is a two-sided wiki:
- one side would be the published version, with the ikiwiki CGI disabled;
- another would be the developement version, which would be editable online.
These two sides would correspond to branches in the repository. Each time someone makes a change to the developement version, the created revision number would be added to a list of changes to be reviewed, maybe by a pre/post-commit hook. This would be done only if a published version of the page exists, and could be requested when a new page needs to be published. Some kind of priviledged user could then move the change around, from the "review needed" queue to the "accepted" or "rejected" ones. This would be done in a way that would trigger the appropriate VCS merge operations.
A generic "change queue" mechanism could be used for translations or other stuff as well. Each change would have its own wiki page under changes/revNNNN. Change queues would be wiki pages as well (probably using inlines); Pagespecs and tags would be used to control the queues to which a given change would belong.
You can achieve something like this right now, by using Git. The development and published versions each have their own repository, with remotes set up so they push either to two backend repositories or to two different branches of the same backend repository. You can then merge from one to the other whenever you want.
You could theoretically do this with SVN as well.
I do like the idea you suggest of reviewing and merging changes through the web interface, though.