I think nervousness about 2nd spinner options meant Somerville was always going to play the 1st test.Oh yeah, I completely get the idea. But Somerville is a very one-dimensional off-spinner. Couple that with the fact NZ went in without any left arm seamers to create rough, and India don't have any either, and it was obvious a lot wasn't aligning in favour of Somerville playing.
Then you add in the fact that Wagner has made a career out of taking wickets in tough conditions, and just that he sits so well in this side in terms of his competitiveness and willingness to keep going. I'm not for one second suggesting that's the difference between victory and defeat, but I don't think we made the right call there.
NZ selectors missed a chance by not picking Ravindra at Lord's in June. Instead they went with conservative option of Santner, just in case they turned up to Southampton for WTC final and found a very brown pitch and wanted a spin option instead of de Grandhomme (who was still coming back from injury).
So now they arrive at Kanpur and Ravindra's bowling hasn't been tested at the highest level, Phillips might take the odd wicket but will leak runs, and Santner is a no-rounder at test level.
If Ravindra had been picked at Lord's he would have batted at 6-293 and could have bowled the 10 + 13 overs that weren't bowled by the 3 quicks + de Grandhomme, and captain and coach might have had more confidence in using him as a 2nd spinner at Kanpur.