Big news indeed. There's been a
press release on this, and
various blogposts with
different opinions, and I'm not sure what there is to add except a personal perspective on the whole issue.
I'm personally very sad to see her go. A very effective politician, a very effective activist working within parliament to generate change from within. Certainly one of the best MPs in the last ten years.
I'm sad, but not disappointed. She's given ten years of service to New Zealand, which, even as a backbencher, is a fair chunk of time. Losing the leadership was, in her own words, "personally disappointing", and that is understandable. I don't think you can begrudge someone their right to resign given that she felt that she had lost the support of her own party's members. (The Greens democratically elect their co-leaders.)
On the other hand, this may not be a loss for the Green Party. Bradford polarised the nation over S59 - and public opinion was mostly against her, as demonstrated by the referendum. A comment on the Greens blog said that she "lives in the wrong century". I agree, she's a century ahead of our time, and in a few decades we will probably wonder why we as a nation fought so hard to defend our right to assault our children. But right here, right now, she's a political hindrance to a party that is trying to extend their influence beyond their traditional grassroot activist voter base.
The woman who beat her to the co-leadership is no slouch either. She's green left through and through, but Norman and Turei are so politically adept that they just might reach through to the centrist but environmentally-concerned vote. They are also more than capable of touching base with the younger professional vote, and indeed I envision that the Greens will become a mainstay of Left politics in the future, especially whilst Labour with Goff sinks into irrelevance.
In summary; it's a big loss to New Zealand, but a politically smart move for the Greens.