Doull said Australia had just one test player in their T20 side while the Black Caps had seven. Williamson, Ross Taylor and Tim Southee were among the players who should be dropped, with the likes of Anton Devcich, Mark Chapman and Tim Seifert promoted. The only regular test players who should survive, in Doull's opinion, were Colin de Grandhomme, Mitchell Santner and Trent Boult.
Doull told the Radio Sport Breakfast: "I don't think we are getting the selections right — I've had some concerns for a while.
"I would like to see Colin de Grandhomme batting higher but it is the selections, not the batting order (which is the problem). We want dynamic players and should be giving them an opportunity at T20 level.
"If Kane Williamson doesn't open in T20 he shouldn't be playing. His record opening is very good, at three and four it's not that great. But he shouldn't be in the T20 side, there's a lot shouldn't be in the T20 side."
Williamson averages about 38 as a T20 opener, and 22 batting elsewhere. He had a shocker in the Tri-Series opener in Sydney, scoring eight off 21 deliveries against the Australians batting at number three.
Doull said Guptill was New Zealand's senior white ball specialist who would "relish the captaincy and responsibility". Coach Hesson, meanwhile, needed the chance to freshen up.
"He's a great coach who has done an amazing job, and has really grown into the job," Doull said.
"But he gets very little time off, only a small amount of time with his family. Give him T20 completely off, get a new coach, new ideas, a new bunch of players.
"(the coach) probably needs to have played the game to understand it a bit better. The Northern Knights had Gareth Hopkins solely as their T20 coach and he played until recently. The rest of the coaches around the country are a bit older, out of touch with T20."
On the Tri-Series, Doull initially picked England as the team to beat but was extremely impressed with an Australian side packed with rising specialists.
"They've got guys with great slower balls, variations, long batting power. It is a very, very good T20 side and I can see Australia upsetting England," he said.
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