We currently have automation that will flip a custom field based on a change to other fields.  It just so happens that these fields that change we need to check are things like Summary, Fix Version, Status....all things common across ALL templates, ALL projects.  

As you suspect, this is out of control with our volume and constantly throttling.  We've worked with our TAM and other consultants to figure out how to streamline this as best we can , but going across 400+ projects with expected volume of 400-500K tickets per month, this is going to be an issue very soon as we grow. 

What would help us out tremendously is the following:

1 - Ability to add scope to the rule by project category, not just project type:  

1. https://jira.atlassian.com/browse/JRACLOUD-78444

We have 1000+ projects we are going to be building so selecting multiple projects is time consuming and we will miss something and creating individual rules for each project -well that's going to be 1000's of rules

2 - Review of the listeners.  Here are a few things that could help make automation easier for clients, especially as you grow your enterprise audience with larger volume and more users.  

1. When field changed:  Add in criteria to pick a certain template... this helps when folks need to check common fields across all templates, etc.  Even doing the condition of template after that check - your logic still pulls ALL changes
2. Issue Created/Issue Assigned/Issue Commented, etc.  :  Add in criteria to pick issue

Doing these quick checks upfront is not only going to help the client, but also take off some strain from your environments.