Can you share more info about the parentheses being a hazing test? I’ve seen Dylan syntax [1], but is there something else that shows the parentheses to be unnecessary in 2020?
In my admittedly limited experience with Clojure a few years ago, IIRC it seemed like it just replaced some parentheses with square brackets, but did not actually reduce the number of total brackets by much.
It's not radical, in that it's still basically parentheses but their nesting is greatly reduced by combination of tricks:
Flattening, if reversible. E.g. if something's always a list of pairs, then it's represented as a flat list with pairing inferred.
Having shorthands in syntax, i.e. [a b c] is (vec '(a b c)).