And what's an 'implicit'?
I would trade real macros for almost any other language feature, as having them means being able to patch over whatever is missing.
The more powerful a language is, the less popular it will be. Couldn't be any other way, since only people with enough experience appreciate and feel comfortable dealing with them.
My point is, readability of code increases proportionately not just to the complexity and size of code, but also proportionately to the size of syntax. In a language with no macros, the latter is fixed and you get a linear dependency. In extensible PLs it's a quadratic one with an unknown second factor, jeesh! I think the approach with a more powerful but almost fixed language (eg Haskell where macros are hard and mostly used to generate boilerplate definitions) is better than a small but extensible language with every programmer on a contest of who makes a wittier and sleeker new control structure that is like the builtin ones but SO much cooler...
Why didn't it happen? Because programmers overall are reasonable folks. So, yes, in theory, you can define a factorial function and call it "Not_a_Cat" (technically, it is true), but nobody does that.
Similarly, giving the ability to define `X in Y..Z` makes code more readable if you use it right, not less.