At the moment, this can be done by adding a FIXME button on top of the page :-) For finding all pages that have to be fixed, you would have to create a page called "Fixme" and link all fixme-pages to it. (Not a very practical way, I know)
An other, more generalistic solution would be, if pages could be tagged, like described in my Feature Request http://bugs.splitbrain.org/?do=details&id=707
You could add taggs like "incomplete" to pages then and find all of them by searching.
I would suggest to close this task, because it is rather special and could be archieved by tagging (Task #707)