I do agree that s-expressions shouldn't be set in stone. But I'm not sure that these specific suggestions are useful. Maybe I'm being a Luddite in regards to change.
I guess I'm on board with the curly-infix expressions for math. Maybe. I do hate having to mentally parse through lines like
{{1 * 2} + {3 / 4}}
To get "oh, this is adding two things together". But ok. Maybe. But the minute I have to distinguish between the form
... fun(arg1 arg2 arg3) ...
and
... fun (arg1 arg2 arg3) ...
I'm done. Granted, I haven't actually used neoteric expressions -- and I should try them -- but until I do, this style looks much less readable to me. I disagree that it's painless; it seems actually quite painful to me. It sure is closer to Algol-style coding, but it's just asking you to confuse the two. And that's easily done.
Fair enough. You don't typically see the no space style in lisp, so it stands out for me. But you're right that it's not as cut and dried as I thought.