The other nice feature of brackets, of course, is that they nest. Half the escaping problem arises because the 'treat this literally' syntax can't be nested: if shells used the Postscript approach of enclosing literal strings in parens instead of quotes, then you could trivially quote any piece of shell syntax you liked (by induction, that piece would contain matched parens if it quoted anything in turn) without having to worry about escaping the escapes.

In fact, doesn't Tcl do that? And also GNU m4, IIRC.