> You can ease the cognitive load by making certain programming structures first-class citizens in the language.

Which, in every s-expression based language I'm aware of, can be achieved using macros.

Isn't that the point - s-expressions aren't good enough so people work around them by writing more conventional languages and parsers (the reader macros) to avoid having to write in them.

I don't think that comment was about reader macros. I don't see reader macros used much, while normal macros are frequently used to create new control structures.

Yes but now you have to worry about parentheses and at what nesting level certain constructs should live.

An adequate editor with autoindent and paren matching solves those problems completely.