The most useful lists for en:wp are at http://en.wikipedia.org/wiki/User:Skysmith/Missing_articles especially the pages under Art. A lot of what is outstanding is rather old-fashioned terms from old encyclopedias. We haven't run a comparison with a big Art biographical dictionary AFAIK. We've been shown the Cooper Hewitt links before - I haven't checked if they still show Napoleon Bonaparte as missing a WP article, as they did a month or two ago!
John