It is getting more and more common these days to size EPICS in T-shirt size, where an Epic that looks like needing a full srpint to get done, would be a "M", 2 Sprints an "L" and so on.

This has an enormous value for project prospection, sales estimates, and backlog management (it is great to be able to know how long your backlog before creating and sizing stories.

We would like to have this as a system field, that we can use for EPICs, and not a custom field we create and that will generate custom formatted data, hard to manage down the road for add-ons, or JIRA upgrades. 

More info here:

https://www.mountaingoatsoftware.com/blog/estimating-with-tee-shirt-sizes 

https://www.sitepoint.com/3-powerful-estimation-techniques-for-agile-teams/