The claim that somehow this retains all qualities of Lisp is absolutely ridiculous. The single most important property of Lisp is that programs are lists, i.e., code==data. "Indented" lisp breaks this.
I'm not intending to troll when I say that people who don't like the parens just don't "get it."
I suspect the reason that alternative syntax for Lisp doesn't fly is that, once you use Lisp enough, you start feeling too comfortable with S-expr and the editor's support on it to switch to alternative syntax. It only appeals to those who are new to the language. And the downside is that the editor support can't be as good as S-expr (I suppose; is python-mode capable of various C-M-something tricks?).
Humans don't think in syntax trees.
In languages with syntax, I have to add syntactic fluff to satisfy the compiler, which is mostly an extra annoyance.
I don't say my way of thinking is the correct one. Some great programmers I respect have said they don't think in DAG (and naturally they choose languages other than Lisp as a primary tool).