Macros are powerful but still a bad idea. Like GOTO - using GOTO, you can implement absolutely any kind of weird control flow structure you can imagine. You have a lot more freedom than the usual if/else/for/while. And you can, if you use it wisely, make code that's more coherent and consistent than any other. But people don't.

Coherence of assignment is a very good idea. But you don't need macros to get it. If you have a language with simple syntax where assignment is just another function call (perhaps via a typeclass), everything in this example still works; it's not the fact that lisp has macros for assignment that's important here, it's the fact that assignment is not special, not handled specially in the parser; it's just another function. You do that, and you get the advantages, with or without macros.

Lisp's lack of syntax makes macros easy, but they're still a mistake; they still lead to unreadable code because you can't tell what a given piece of code does until you understand which parts are macros and understand all of them. Give users more structured ways of achieving the (often quite small) number of things they want to do with macros. If they need more things, add those things as first-class features, the same way e.g. exceptions were added when people realized if/else/for/while didn't capture all the use cases for goto. But don't throw up your hands and let every library rewrite code willy-nilly.