Isa Nacewa: You cannot underestimate the job Michael Ceika has done with Australia over the last year
I think we can all agree that this World Cup was the best yet. It needed to be an exciting tournament to live up to all of the hype and expectation that went before it and for me it definitely delivered.
It really kicked into gear when Japan beat South Africa. It was champagne moment and it gave everyone else belief.
The gap between the top nations and the lower ones was narrowed and that can only be a good thing for the game going forward.
More and more players are beginning to play their rugby in Europe and the likes of Georgia, Namibia and Japan are all reaping the rewards.
Four years ago, New Zealand put 100 points on Japan but that, thankfully, isn't happening any more. You can see the incredible work that Eddie Jones has done with Japan and there were a lot of other teams who also made great progress throughout the tournament.
For me, in four years' time, everyone is going to be talking about Argentina. They were the nicest surprise package of all. Their style of play is really exciting and they are only going to get better over the next couple of years.
Graham Henry's stamp is all over their game plan and I genuinely believe that they will be serious contenders for the title in Japan.
International Rugby Newsletter
So often in the past, the World Cup final has disappointed and you only have to look back at four years ago in Auckland when the All Blacks' victory over France was pretty uneventful.
This time it was different. This time you saw New Zealand digging deep and turning it on when it mattered most.
Their ability to perform the basic skills under the most severe pressure coupled with their mental strength is what sets them apart from the rest.
They play the 80th minute as if it is the first. What I mean by that is, their concentration levels never drop. They pride themselves on maintaining that consistency and they very rarely make sloppy errors.
Back in 2011, people questioned whether or not Ma'a Nonu and Conrad Smith were the best centre partnership. Four years later, they are still delivering on the biggest stage.
Nonu is a player who I don't feel has gotten enough credit for what he has done in the game. For me, over the last three years he has been one of the stand-out players in the world.
People will invariably look to the likes of Richie McCaw and Dan Carter as being New Zealand's talismanic figures but there were times when Nonu carried that team.
Legacy is often spoken about back in New Zealand and there is no doubt that this team has left something special behind them. The biggest challenge they face now is rebuilding to the same high standards.
The greatest teams are judged on what is left behind and in years to come, people will definitely look back at this All Blacks team as being one of the greatest.
I think any of the top six teams in the world can beat the All Blacks on any given day but they very rarely lose two games in a row.
In my eyes, Dan Carter was rightfully voted the player of the tournament. It's amazing to think that for everything he has achieved in the game, last weekend was the first time he has played in a World Cup final.
Having been overtaken in the pecking order by Aaron Cruden, he has clawed his way back to the top and what a way to end his All Black career.
In terms of a 'breakthrough player', Nehe Milner-Skudder was immense. When you consider that Israel Dagg and Cory Jane didn't make the squad, you get a fair idea of the All Blacks' strength in depth.
Milner-Skudder shone through the bright lights and is brilliant for the game. He's not a 6ft2ins 100kg winger and kids watching him will realise that you don't have to be a giant to play the game at the very highest level.
Because New Zealand won the last World Cup, Steve Hansen said that the success would allow him to do things differently and he stuck to his word.
Hansen was more willing to take risks and selecting Milner-Skudder showed that. The easy thing to do would have been to select the tried-and-tested guys like Dagg and Jane.
Michael Leitch deserves a mention for what he achieved with Japan. He played with the Chiefs back in New Zealand and was down the pecking order but he had a brilliant tournament.
In my view, Michael Cheika was the 'coach of the tournament'. You cannot underestimate the job he has done with Australia over the last 12 months.
Cheiks has completely transformed the Wallabies and they will come back stronger again. It's going to be a tough ask for Japan 2019 to be a better tournament but I think it is possible.
It is crucial that the scheduling is made right for all teams so that they can build and develop over the next four years. The likes of Fiji, Japan, Namibia and Georgia need to be playing games against high-quality opposition in order to develop.
That will inevitably drive the standard of the worldwide game up another level and if in four years' time, we arrive at a World Cup with that in place, it's going to be another very special tournament.