... until your jinja templating breaks for some obscure reason, or the underlying terraform resource upgrades (they follow the provider api after all), or if you need to do some state surgery and partition one terraform state into multiple ones, or until you want to import resources into the generated terraform or....
Apologies, I don't mean to be a downer. But... you're making your present life easier but making the code harder to maintain for future maintainers of your codebase.
What's the more maintainable alternative? Is writing repeated constructs etc out individually really more maintainable, or are you referring to other ways of getting these things reduced?
I highly recommend taking a look at the AWS CDK. It's a relatively new project, still in beta and hasn't gotten a lot of attention yet. It allows you to use real programming languages to generate Cloudformation templates. In my eyes this is the best of both worlds.
Apologies, I don't mean to be a downer. But... you're making your present life easier but making the code harder to maintain for future maintainers of your codebase.