I believe I've reached a point in my career, and used Terraform enough, that I can confidently say that the semver system for managing IAC code bases simply doesn't cut it anymore.
I'd love more widespread feedback on how I currently propose we version control our IAC. If the feedback is constructive and forthcoming, I'll move this written piece to a more formal location.
This is currently being tested, with extremely positive results, at Cisco (yeah, the networking company.)