Specifically, Red is a dialect of Rebol, not Lisp. And after a quick glance through the docs (or I guess the Rebol docs they recommend using), and the Wikipedia pages for Red and Rebol, it doesn't seem any more Lispy than Ruby or Python.
Also, the easiest way to get a lot of libraries would be to have easy C interop. At this point there are far more C libraries available than Go libraries.
Homoiconic syntax is one of the features of Lisp that people know the best. REBOL and Red are homoiconic, while Ruby and Python are not. This means that syntactic extension, which is impossible in Python and Ruby without modification of the parser, is easy to do in those languages. The other similar language (besides Lisp and REBOL/Red, excluding Forth and some more esoteric langs) is Tcl: it's also homoiconic and enables easy syntactic extension.
And you have C interop today, though it will get easier in the future.
Does that go for the binary distribution only, or also if you want to compile the source yourself?
R3 is open source (Apache License), but Rebol 2 is proprietary.
It seems Red is not comtaible with Rebol3 (or I did something wrong).
Too many brackets is rarely the initial complaint. Usually people complain about the lack of parens in function calls. Free-ranging evaluation is an important design element, but it can take some getting used to. One of those "With great power..." things.
Once you start writing in it you realize how much the syntax often reads like an English sentence. And the brackets make perfect sense when you begin to understand blocks. And besides; its no more than curly braces in C and definitely fewer than parentheses in Lisp.