There are quite a number of issues to look at.
Text edit
There are articles that are headers alone: see Category:DNB Add text. There are also articles to be found in Category:Incomplete texts without a source and/or linking to Template:Incomplete.
For particularly bad text in pagespace, apply Category:Problematic DNB pages, text.
Djvus edit
Category:Problematic DNB pages, djvu is the subcategory to populate where the djvu is illegible or distorted, or otherwise corrupt or obscured. So far Category:Problematic has mainly been used.
Titling edit
Pages will in some cases need to be moved, as the Style Manual is hammered out. The volume ToCs use disparate conventions right now, also.
Hypertext edit
Any DNB00 article should be linked from two pages (Author page and volume ToC), and from the previous and next article. Magnus's tool shows up various types of issues with the Author page link. One of those is where the author template {{DNB XYZ}} links to a redirect to the Author page; this can be fixed once-and-for-all by an edit in the Template page.
There are still perhaps a few older pages where the "wikipedia" header field is deliberately blocked; remove whatever placeholder is there so that the page can be placed automatically into Category:DNB No WP.