I was about to say this in the other thread but I'll say it here. Guptill shouldn't even be considered for a second for the World Cup, as a squad member or otherwise.
For a start, he's in poor form in the BBL. 164 runs at 16.4 in 10 innings - good enough to be 10th in the averages. Oh yeah, I should point out that's 10th in his team (Renegades).
Secondly, and most importantly for me, he chose not to fight for his spot. Someone in the other thread I think said 'good on him' or something for being dropped and choosing T20 cash over trying to get back in. Not me. He took an NZ contract at the start of the summer, was happy to play for NZ at that time, but then decided to hand it in at the first sign of being dropped and on the outer. Not 'I'll fight back, I've made a career of runs for NZ and I want to play in the World Cup'. His World Cup record is poor (save for the Windies double hundred, he's never fired a shot in a meaningful game) and if he doesn't have the burning desire to make up for that, and 2019 - which he's exhibited - then no interest here in him being considered.
That's even before getting to thirdly, which involves the morals of making Player X the expert columnist in the national paper and the bemusing stuff he wrote. Talking about 'going hell for leather' with Guptill at the top - ignoring the fact he never starts quickly - and dropping Conway down one when he's in prime form as an opener, ha no thanks.