I'd rather live working around some oddities than with nothing at all.
But it's a false dichotomy, I'd say: nothing prevents them from being more agile and correcting any issues that is found in the spec in a dot update. A few people will have to update their code, or use some conditional code, big fucing deal.
Or they could, you know, provide a reference implementation -- e.g working with Mozilla or anyone interested.
Release it as an opt-in engine (e.g with something like "use strict") fix any issues that arise for 1-2 years, and make it a finalized standard from the on.
OTOH if things are rushed then you end up with underdefined oddities and weird effects of things that seemed sensible: http://wtfjs.com/page/13