Yeah, NZ are out in front, but are not looking quite so invincible now - not so much due to themselves, but a lot of other teams are looking improved, and there are many who will be fighting for the semi's and if they click on their day could test the kiwis
NZ seem to have a slightly weakened midfield since Tana's retirement, the replacements have comparable skills/abilities, but possibly not the same experience or decision making. If McCaw's concussion prone bonce takes a knock then their confidence will take a serious knock, they finally lost a game too...
So after that you have quite a few teams, that could easily turn it on:
South Africa - on pure ability and form probably second placed
France - home team will make the french play to their best
Australia - always very professional, came from nowhere to the final in the last world cup, cannot count recent form, also beat the AB's
Ireland - Were playing magnificent rugby, and until recently were stuffing everyone they played,
Wales - wierd things happening with wales, don't really understand where they're going, but if they get their internal problems sorted out can play devastating rugby.
I hate to say it, but even england maybe start being worthy of a mention, if they manage to put in another improving performance against france in paris