The first bit is exactly the justification for the second bit. 'Doesn't look at all like scoring runs and hasn't all tour' is not a stupid argument for leaving a batsman out - it's saying 'who will likely contribute more in the next match?' and answering 'someone else'. The counter argument that you seem to be supporting is to weight more heavily the pick-and-stick approach - that incumbents have a certain amount of credit they've earned that they consume through failures, and that consistency in this approach is fair and good for team morale even if it occasionally leads to worse immediate outcomes. That's fine and I do often favour the latter. The logic only goes so far though when, with the next match in sharp focus, noone has any confidence he'll score any runs at all.
If we'd lost the first test I would've absolutely left CDG out for the second. As it stands, given the shortage of other options in the squad I would be tempted to close my eyes and just go with the same, hope it magically works out ok, that he takes a few more wickets and that we can do without any runs from him. It's pretty much a coinflip. I think the NZ selectors will indeed retain him so we'll find out soon enough.
i can't get behind this at all. "someone else" who can bowl (so not Blundell) averages less than 20 in test cricket with the bat and bats like a moron, or a guy who averages 12 in FC. Colin is an infinitely better batsman than both, and he provides the 5th bowler.
further, dropping someone based on the result and for the sake of finding someone else, even when there isn't someone else, is ludicrous. that's what weak teams like nz 2006-2012 do. that's how you end up like nz and england of the 90s.
colin has a job and he will get more than one test to complete his job. he will also never learn how to bat in spinning conditions if he is dropped the moment he fails in them.
there are wayyyyy better arguments you could use to justify dropping colin (not all of them arose this test but potentially could this series)
-we need more specialist batting depth, so we will pick blundell and use kanes offies more
-the conditions support spin so much we need 3 spinners, so we will include somerville
-we need more pace bowling to make breakthroughs faster and rotate boult/wagner more, we will pick southee
those are all reasonable arguments, even though they take risks with our batting or bowling depth.