The IT at my current work designed infra as such :
One repo for ALL the configs for every project and one config file per project that defines the version of the language (ex node 6) for all environment of a project. I don't even want to talk about deploying previous version or what happen when you update the version and AWS spawns new instances.
Jump into chatops hype approach and use one single script to deploy every app. Talk about a single point of failure but hey we use slack now it's great no?

Since I always think we are one character away from bad deployment and I'm into one click deployment then I've made a web app just to generate command and copy it or send it to slack.

I guess this is what happens when IT work for themselves only..