Savea is a game-changer and the All Blacks will always need one of those.
Smith is a gifted, all-round footballer who I like on the wing or at fullback. I don't think it matters which position he plays - although I think he is wasted at centre - because he's able to have a positive influence on the game from either.
Having played in Ireland for four years, I know what conditions will be like on that side of the world at that time of year. So it's important to factor in the weather and style of rugby the All Blacks are likely to encounter at the World Cup.
The Six Nations this year hasn't delivered a lot of tries. The various teams are playing more for territory and look a bit cautious and fearful of making mistakes.
Israel Dagg is a player I really like when he's on form and backing himself to run. But he also has skills that could be invaluable at the World Cup. He's got a huge boot, is good under the high ball and has plenty of experience - all of which are important.
The All Blacks will be wary about running themselves into trouble from deep in the big games. There will be counter-attack opportunities but it's knowing when and how to take them.
That's why I would be happy with a back three of Dagg, Smith and Savea. But I'd be just as happy if it was Cory Jane, Smith and Savea. Jane is another with experience and the ability to cover wing and fullback.
It's obviously going to be a difficult job for the selectors making the final choice, but it's not something the players can get caught up thinking about too much during Super Rugby.
They won't be oblivious to the bigger picture and lingering in the back of their minds will be thoughts like, 'what if I have a bad game? What if someone else in my position is playing really well?'
But they can't get caught up thinking too far ahead. They have to play their natural game, fit in with their team's patterns and be confident that if they do, they will get the rewards.
