That being said, re: Python 3, you should keep a close eye on Zappa (https://github.com/Miserlou/Zappa) - as we've got a surprise in store that may delight you!
It would be pretty simple to wrap this up and automate it easily using a Terraform file. All it requires is an S3 resource for the ZIP, a Lambda resource using the S3 resource for the code, and finally an API Gateway resource to tie it all together.
Thoughts?
We already use CloudFormation under the hood for the API Gateway, though to be honest I'm seriously considering moving away from it because it's so fickle.
There are also some security disadvantages and other problems from using CloudFormation for maintaining Lambda functions, plus you lose out on all the extensive functionality we provide. We're pretty damn well battle tested to avoid that stuff now.
What you're offering is awesome, for the record. I think it's a good idea, I think it's powerful, I think it's fast. It's a good idea and you should keep working on it.
However, it's a single, small Terraform file worth of work from my perspective.
Thank you for making it though. It's a really cool part of the Lambda ecosystem. Excited to hear there's something in store for Py3 :)