I would block all tags until you create new content for each tag.
SInce it's wordpress you can create a tag php file and add content into it. Then you can add that tag to your sitemap and remove from robots.txt. That way you avoid duplicate content and boost the site with more seo friendly content.
You should create php files for each tag and just work on them one at a time.
For example you might start with tags-seo.php then tag-design.php and create specific content for those.
