How would you handle a shitty PR4 site?

I have a PR4 financial site made in 2008 and there has been no new posts since then. Barely any traffic, about 50 visitors per month. Only 12 sites linking in but 3 of them are PR5s and 1 is a PR6. The content is unique but boring, useless and outdated.

Would you build on the site or make a new site and redirect the PR4 to it? I want to do a redirect cause I want to do a wordpress site and this shitty PR4 is using drupal. Considering this, what is the best way to handle this situation for the long-term - redirect or build and possibly have it migrated to wordpress?

Personally, I'd update everything about the new site. Then create an entire new diverse backlink profile to it a few days later. Then start with some social campaigns to get it more exposure.