Well, no, it is self-inconsistent in places [0]. However, as you mention, those are probably minor points compared to how it contradicts existing standards, like the Gregorian calendar [1], date representation, and language codes.

0: http://www.groklaw.net/articlebasic.php?story=20070123071154...

1: http://www.groklaw.net/articlebasic.php?story=20070123071154...