I like scheme a lot; and the parentheses never bothered me. But one device which could provide a gradual path through the thicket of parentheses, and perhaps make Arc more inviting to beginners, would be the:
hide/show invisibles
of word processors. There could even be levels:
hide/show some invisibles
hide/show more invisibles
hide/show all invisibles
Yeah, personally I don't really care whether this is even a language feature or an editor feature. The ability to hide/show more or fewer is certainly interesting.