It would be a great feature if we could decide to have only unique content names.
At this moment, when we publish some content, eZ Publish automatically checks if a content with the name name/title already exists in the same location, and if it already exists, a numeric value will be appended to the URL alias of that content being created.
Example: If "MyArticle" already exists with URL alias "/MyArticle", a second object with the same name with have URL alias "/MyArticle2".
The point here would be avoid appending "2" or "3" to the URL alias if a match already exists, and not publishing it instead.
This can be done by using a before publish workflow to stop the publishing process if a content already exists with the name name/title on the same location.