[x3n0ph3n3]

One of the best parts of CloudFormation was their introduction of Macros. You can take either your whole template or just a snippet, and perform dynamic transformations by calling a lambda. I'll admit I've gone so far as being able to embed ERB (Ruby) into my templates in order to more dynamically define some resources based on stack parameters. I can also create N resources with common configuration based on the values of a CommaDelimitedList.

[throwaway894345]

I think the idea here is that macros are neat in any language, but in CloudFormation they can help automate stuff that is only difficult because of CloudFormation, and the macros themselves are harder to use than those in a normal programming language. In all cases, I think it’s strictly less nice than generating your CloudFormation YAML with Python or similar.

[x3n0ph3n3]

The problem of generating your own YAML is you end up having to maintain multiple copies of nearly identical templates and keeping them in S3. I have done a bit of that and maintaining those as build-time assets rather than run-time assets is less appealing. Granted, that's required whenever you get into the realm of dynamically-determined sets of parameters.

[throwaway894345]

Yes, this is another problem with cloudformation, although IIRC I just used “aws cloudformation deploy” and let it manage my s3 resources.