Such a plugin would be very welcome, because it will reduce the effort needed by website developers to be able to play by the rules.

In the article it says:

This is not an easy task as the burden of compliance falls to the website owners, not individual plugin developers.

However, we can expect website owners to install only GDPR-compliant plugins in the future. Given 2 plugins that offer the same functionality, one being GDPR-compliant and one not, the first one should be the preferred option. So, all plugins should strive to be GDPR-compliant (whatever that means) as much as possible, and the "GDPR for WordPress" project could help achieve this.