[praptak]

I've had good experience with Closure's cautious approach to parentheses.

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)).

[WalterGR]

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.