1980s NZ team
Hadlee : Arguably the best ever
Chatfield : Average of 32
Cairns : Average of 32
2010s NZ team
Boult : Average of 27.5
Southee : Average of 29
Wagner : Average of 27.5
The 2010s NZ team performed more consistently
I've given your post a Love icon because of this: "Hadlee : Arguably the best ever" and also because the wolverine (along with the honey badger) is my favourite mustelid.
However, I think Subby is right here (which is why I have Liked all of his posts, I doubt it will ever happen again). Making an intellectual analogy, sometimes the super brilliant individual is required to crack the really hard stuff (e.g. Einstein and general relativity) and a group made up of many just brilliant individuals will not get the job done.
Anyway, I think I can prove reasonably convincingly why Subby is right. Firstly, it is only fair to compare the 1980s and 2010s NZ teams against the same opposition, and by the same opposition, I mean the same in terms of quality. And that means against the best teams because those results should be weighted far more highly than results against minnows. Also, the 1980s NZ teams played against far fewer minnows (just SL).
The top five teams of the 1980s (apart from NZ) were Australia, England, India, Pakistan and the WI.
For the 2010s teams, it would have been the same but with WI replaced by SA. You could possibly replace Pakistan with SL because while Pakistan has a better win-loss for that decade (33-37 vs. 31-40), SL holds an edge over Pakistan in head-to-head win-loss (7-5). I'll include NZ's results against both of them for completeness.
The Pakistan and SL data for that decade (to confirm my previous figures):
OK, here are the overall results for the 1980s NZ teams:
And here are the opposition team results:
You can see that we held our own against England, India and Pakistan. We lost narrowly to Australia (win-loss = 4-5) but if Morrison had been given that plumb LBW against McDermott in the 1987 Boxing Day test, it would have been 5-5 (not necessarily, of course, as the future would have been changed: there was a drawn test at the WACA in November 1989 in which Hadlee did not play for some reason). We also lost narrowly to the WI 2-3 (admittedly, the 1980 "win" against them was a bit, shall we say, controversial, thanks principally to Freddy G!).
Here are the overall results for the 2010s NZ teams:
And here are the opposition team results:
You can see that we did well against Sri Lanka and Pakistan (the two weakest teams) with win-loss numbers of 7-2 and 5-3 respectively and we held our own against England (3-3). However, we got absolutely hammered against Australia (1-9), India (1-6) and SA (0-5).
Against the top teams (especially the best of the top teams), the 1980s NZ teams were definitely better.