A program written in Arc' has the same number of characters and tokens, but the specification of Arc' is slightly larger than that of Arc, so the languages them

A program written in Arc' has the same number of characters and tokens, but the specification of Arc' is slightly larger than that of Arc, so the languages themselves aren't quite equivalent. But, point taken. Power involves succinctness, simplicity, orthogonality and generality; Arc' certainly fails simplicity and orthogonality. And, surely it wouldn't be too hard to write an editor mode to automatically toggle the braces and parens as needed, so with that enhancement writing Arc' would feel only slightly more awkward than writing Arc. The size of the language specification is what affects the ease of writing tools to manipulate it.