As far as tests go, both sides will be without their elder statesmen (Lara and Fleming) who played in the last NZ-WI series.
Players who will definitely and probably be missing from the upcoming tour are:
Fleming, Bond, Astle, Styris, H Marshall.
Lara, Lewis, DR Smith, Bradshaw.
Fulton and Franklin iffy at this stage, it would seem; a question of fitness and form
Not sure of the chances of a recall for Ganga and Morton, Liam or Xavier would be able to tell me (I hope!).
New Zealand probably weakened more than the WIndies, without Fleming, Bond, Astle or Styris in the tests.
Morton and Ganga may be more of a loss than it would seem, if they do not make it, as they were #1 and #3 in averages last tour.
The West Indies attack will actually be fairly similar to last tour, with Powell, Edwards, Taylor and Gayle. Bravo was injured so played as a specialist batsman, IIRC. Possibly Sammy and Benn will play, or Juggernauth, or Miller or Mohammed. That spinner spot is anyones guess really, but I predict Gayle will outperform whoever gets picked (though I am a fan of both Benn and Juggernauth).
As I mentioned earlier, NZ tend to struggle against genuine pace in some ways. For example, Edwards and Powell struck at 44 and 42 respectively on the last tour, indicating quick wicket taking (obviously), but with high economy rates so it balanced out. Nearly 3 years have passed, and with experience they should perform better than that tour.
On New Zealand's side, returning will be Mills, Martin and Vettori. Possibly Franklin too.
Last time, Mills carved up in his only test, and all the bowlers shared the wickets around evenly (Mills 6, Vettori 7, Martin 8, Franklin 8 and Bond 8).
NZ will be boosted by Oram, who missed out last time, and a more experienced Mills, an improved Martin and the captain Vettori. Gillespie, O'Brien and Southee are all possibles, but I expect the attack will be lead by Mills and Martin. O'Brien is actually the incumbent, and took 4 wickets in his last test, which may be enough to seal him a berth in the first test.
Batting wise, NZ hardly resemble the last time these two clashed. How actually played in the last series, scoring 57 runs @ 19 in 4 innings (1 not out). As we've seen against and in England, he's greatly improved since then. Whether or not Redmond will be retained is yet to be seen, but it won't matter as we'll still be going into the first test with a 'new' opening partnership.
I guess Bell is an outside chance to be recalled - possibly all down to the first rounds of domestic cricket. Or Watling could swing a cap if he goes well on the A tour. Cumming a remote chance, too.
The middle order looks patchy. Hopefully someone will be called up to replace Hopkins and McCullum will take the gloves again - perhaps batting at around 5 in the order. Ideally I'd like to see How, opener #2, Fulton, Taylor, McCullum, Flynn, Oram, Vettori, Franklin, Mills, Martin. Bats to 9, sort of, with plenty of bowling.
However, I think only two of those people would make it ahead of current WIndies top 6 - How ahead of Chattergoon and Taylor ahead of Marshall (Gayle, How, Sarwan, Taylor, Chanderpaul, Bravo). McCullum is better than Ramdin, while our tail is vastly superior in batting to the WIndies - something that could be the deciding factor in how the tests play out.
I think it will come down to three simple factors:
How much the pitches favour the bowlers.
If the NZ bowling attack can dislodge the class, experienced, WIndies batsmen (Gayle, Sarwan and Chanderpaul).
If the new NZ batting line up can withstand bowlers who bowl faster than they generally face.
If J Taylor and Chanderpaul are on song, I think we'll see a 1-0 WIndies victory, with the first test being a draw. If Mills, Vettori and McCullum are at the top of their games, I think we'll see it 1-0 in favour of NZ.
I think it will be a close series. Closer than most people will be thinking, and closer than anyone could hope for. I wish it was longer than 2 tests.