It would be great if there was a JQL function which returns issues based on the number of linked issues, and also the link type. For example, let's assume we have an issue which is blocking 3 other issues (using issue link). Using this JQL, we can find this issue easily

Use Case:
In a system, there could be many issues some of which are only blocking 1 other issue, while others which is blocking 5 issues. We would like to resolve the issue which is blocking 5 other issues first. This query will return all corresponding issues, and omit the unwanted issues (blocking less than 5 issues)