On the next wicketkeeper, I think everyone including myself has the tendency to focus disproportionately on the wicketkeeper's batting at times. Probably because it's easily seen and quantified, while good wicketkeeping is mostly anonymous. Blundell has done a decent job overall but, between his form behind the wickets the last couple of seasons and Latham/Conway/Seifert's increasingly error-ridden keeping in limited overs, it's a reminder that actually it'd be really nice if our wicketkeeper could just catch everything, not break fingers, take runouts, organise the slips, be tidy and not concede byes.
NZ has been fortunate to have had a line of long-serving ultra-reliable wicketkeeper-batsmen over the last few decades - Watling, McCullum, Parore, Smith - with gaps of only a few years in between. We're looking for the next one of those, ideally in all three formats.
Hay does seem like the one who could potentialy be it for all three formats (due to his batting). But, I hope his glovework is really good or can be improved, like Watling did. Chu will get chances too, you'd think, same goes for him. Overall, recency says we need to value pure wicketkeeping quite highly, especially in test cricket.