Maybe 'nostalgia' wasn't the right word for the views on Reece Young - what I mean is that people like you are now saying he was dropped too early - which I have sympathy for because I think wicketkeepers should be picked firstly for wicketkeeping (and he's not a terrible batsman anyway - if we'd had some patience). But people looked at the truckloads of runs being piled up by in domestic FC by Van Wyk (and De Boorder the previous season) and all that 'potential' present in Watling and wanted mooooooooooore from a keeper and pulled the trigger prematurely on Young. And no surprises, it hasn't worked out so far - Van Wyk hasn't found his feet yet either after a similar number of tests and may not at all. Now we all apparently think Watling is going to be a good batsman-wicketkeeper based on a few fifties in some ODIs vs Windies - he really hasn't shown a lot apart from that. Let alone the keeping part. Yes he definitely has more upside than Van Wyk but he comes off a lower base too - would need at least a year of guaranteed place in the side to maybe come good.
All I'm saying is, Young was dropped too early, let's not do the same to Van Wyk. All we can expect is someone to do the job for 3 years and average 20 with the bat - a Robbie Hart. Fact is Van Wyk scored bucketloads of runs in NZ domestic FC (to the point where PEWS was saying he could make it as a pure batsman iirc) so if he can't score runs in internationals I don't like De Boorder's chances. And his keeping has been pretty good barring the communication between him and Taylor, which needs to improved.
As for Martin, if you want to get rid of players with no upside or room for improvement then he's it. And we have alternatives. Yes it's a little sad but as I said before, I think the right thing to do after he was dropped in the West Indies would have been to retire and make room for the guys coming through. Where Southee failed, Boult and Bracewell now are settled in the seam attack, so Martin can afford to call it quits.