I'm a very small-scale, amateur programmer, but that sounds like over-engineering to me. Getting variable values into strings is often necessary. A programming language shouldn't make something common hard, just to enforce a particular view of best practices. Note: I'm not saying that "make it a method" is a bad idea - in general or in the case of a specific project or a specific size of codebase. But I don't like the idea of the language enforcing such a restriction.

Having said that, my first language was Perl, and I'm still a fan of TMTOWTDI and making common things easy.