The big 3 refers to money. Not skill. Otherwise someone would need to explain how SA was #1 for so often. And why Australia and England are still not in the top 3 on the rankings - but very much part of the "Big 3".
That said, your concern does not apply to Nicholls. Nicholls has centuries against Saffirs and England (the day night match where NZ rolled England for 60 odd) - but his real crowning glory was a century in the UAE against Pakistan against Yasir Shah in full force that helped NZ win a series there. He is currently ranked #5 in tests, with KW ranked #2. Taylor is 12=, Latham 11 and Watling 30=NZ has had a good time of it lately winning 5 series in a row vs Eng, SL, Pak, Bang, and WI. 5th day rain Rain robbed us a series vs SA. But that's cricket. Raval, currently ranked 34, averages over 60 vs SA but 8 vs England.
Latham is a minnow basher through and through, though. His runs have all come against SL and Bang at home, Zimbabwe and West Indies. He really needs to remedy this. India, Eng and Aus are all playing us this summer. Either openers in Latham or Raval may well end up dropped at some point for Will Young if they struggle for runs. NZ has a gun not in the team, and he can bat anywhere. Taylor will get a free pass in tests, cos of services rendered and his importance to the ODI team.
Latham is fine and classical wisen-type technically, and is known as one of the premier players of spin in NZ. Which begs the question why is he opening?He has 3 modes of dismissal that are memeworthy, chasing the cover or wide off drive on the new ball and nicking it before he is set. Or looking to clip to the leg side and being lbw. Which all raises the question why is he opening? Then once he is set 30 to 50, he is famous for clipping the ball to leg straight to a fielder for out caught.
Nicholls is not at all technical like Wisden. He has some of the sweetest cut shots you will ever see, and a very good sweeper. His pull shot makes him some runs but looks awkward at times, but he hits to different areas I believe intentionally. However, he has next to no straight drive game at all. He looks to whip on the onside. Or square and cover drive if very wide. And he has a huge gap between bat and pad, and is often clean bowled through it. Even on his forward lunge defence. Nicholls basically has a game plan like Allan Border did. Without the defence as yet. But as he showed in the UAE, he can make it work against the spinners.
Nicholls is a very square based player. Latham is 360. I believe when Watling retires, Latham will move down the order and become the wicket keeper. Latham is not an opening batsman. And despite him crushing some minnows, has not performed all that well as an opening batsman. The spanner int he worls for this happening, is Tom Blundell has been ear marked as the next test keeper, and been with the squad for 2 years now as the spare.
Nicholls just looks more and more composed every intl innings. Even his 50 in the WC final, he just seemed like he was in control. I thought he was set for a 100 tbh. The irony is, Latham was dropped as odi opener, now Nicholls is the odi opener. These 2 swap roles per format. They're from the same province - and both can keep wicket.