HCL is atrocious. Terraform's main issue is that it tries very hard to be declarative, then it has to invent a template language as a superset of the declarative JSON it uses to make up for it. And that superset is invariably shit.

It's like you said; no loops, no proper variables etc.

Terraform itself though is fantastic and powerful. It's lacking some pretty important stuff still (for example, not having to refresh the entire infrastructure state when you change one single variable for one single tiny little service), but that just makes it an alpha. It's still better than the alternatives by a mile and then some.

But, yeah. Fuck HCL. The good news though is that I think this is "easily" fixable by someone who would really work on it: Because the underlying environment is 100% json, it's easy enough to generate; so you could implement a saner environment for specifying the state and feed that to terraform. That's enough for me to bet my infrastructure on it: knowing that today's issues are fixable, rather than the effort being doomed from the start.