I could see taking this approach if the outer-most pair of parentheses was implicit. Could be this is how it's already done? I've never tried a Scheme shell.
Interesting! I've been using F# lately, which perhaps shows the limits of the idea. I find myself wishing all of the expressions were parenthesized. Which surprises me a bit because my day-to-day language is Python and I'm entirely comfortable with significant whitespace in a procedural context.