As I've mentioned elsewhere, I agree, but I think in an ideal world, there would be an explicit syntactic construct warning everyone where the program was using the escape hatch to leave the Turing-incomplete subset.
You could create and use an embedded DSL tailored specifically for your application. This is what Jenkins does with their "declarative pipeline": it's basically Groovy-based DSL, and if you need anything not covered by it you need to use `script { ... }` element.
The problem here is of course how not to make your DSL suck, which Jenkins' did not avoid. But if you're lucky, your language of choice already has a few libraries implementing embedded DSLs for configuration, and it's quite possible that at least one of them is actually usable.
