I'd suggest building an auto-upgrade system on top of Arch (or Alpine), and go for immutable infrastructure as the selling point. That's stepping on CoreOS's toes a bit, but I haven't seen any progress from that crowd ever since Red Hat bought them, so it'll probably get even worse now.
That way you can target AWS/Azure/$OTHER_MODERN_STUFF in a more focused way, and you won't be stuck on supporting months/years old versions of the OS.