Currently the links generate JQL which just selects the issue keys in the respective regions.

But for Epics, we actually have the right JQL clauses to generate the searches smartly.

Example:

Completed Issues - "Epic Link" = <ID or Key of Epic> AND status IN <done statuses for this board>

Incompleted Issues with Estimates - "Epic Link" = <ID or Key of Epic> AND status IN <statuses for this board which are not mapped to Done column> AND <estimate field for board> IS NOT EMPTY

Incompleted Issues without Estimates - "Epic Link" = <ID or Key of Epic> AND status IN <statuses for this board which are not mapped to Done column> AND <estimate field for board> IS EMPTY