Many of my users deal with lots of repetitive tasks and we're looking for good solutions to populating possibly hundreds of related issues at once, with some flexibility such as variables.
There are many solutions in the marketplace, but most of the ones I'm finding, are either geared towards templating field values when creating an issue, or templating the creation of an epic, or a whole project.
As one PM said, he wants an ala-cart style menu, I need 2 of these, 1 of those, and a bunch of these...
We're kinda doing this now with csv import. Teams have fairly complex spreadsheets they've created with issue links, and estimates, due-dates etc. They check off the issues appropriate and run some macros to generate the csv's with text replacement in things like Summary, Epic Name, dates, etc.
CSV imports come with some restrictions though such as who can do them, and what they can do with them. For instance, cascading select is limited to the first value only, and custom fields from addons are a challenge.