Custom Machine Executor AMIs
In the same way customers can create their own custom Docker images for execution (https://circleci.com/docs/2.0/custom-images/), it would be a great feature to have custom AMIs for the machine executor. Just tell us what needs to be pre-installed on these AMIs to run on your system.
This is especially useful for:
Cutting down build time associated with installing specific dependencies on a clean box
Removing complexity associated with installing specific dependencies programmatically