Suggested feature:

Instead of just applying notifications to workflow steps/transitions, and then grouping the notifications into a scheme applied to projects - can you also add a "caveat" to the scheme whereby JIRA only executes the notifications in the scheme on issues of a particular priority, or issues of X priority and/or higher/lower?

So you still create the scheme as current, and then you also select to apply it to say "all" issues by default, or apply it to issues of X priorities in whatever project uses the scheme.

This would allow project teams to reduce email traffic (seems to be popular) by directing notifications to specific project roles ... ie "minor" issues can be directed to a Project Coordinator, while "major" issues can also be directed to a Project Manager.