Former England captain Michael Vaughan questioned the team's approach despite their commanding second Test victory over New Zealand at Headingley.
England dodged the showers to take the four wickets they needed on Tuesday's final day as they wrapped up both a 247-run win and a 2-0 series whitewash.
Vaughan said England had been a "bit safe and fearful" after current captain Alastair Cook opted against enforcing the follow-on.
England batted on until after lunch on Monday before setting New Zealand, who had suffered back-to-back collapses, a target of 468 -- 50 more than had ever been made to win in the fourth innings of a Test.
"If they're honest, and they should be, they will look at where they could improve tactically. With strategic aggression they could have won this game already," Vaughan, who backed Cook's decision to bat again, told BBC Radio.
"I think batting again was a good decision but they could have been a bit more proactive (in the field)," he said. "Everyone should have been catching: try to force the batsman into an error. I just thought it was a bit safe.
"It would worry me if they don't sit in the dressing room and accept they've played it a bit too safe and been a bit fearful," added Vaughan.
"They didn't get it right and you've got to be honest as players."
Graeme Swann took 10 wickets in the match but Vaughan felt the England off-spinner did not have sufficiently attacking fields given the hosts' runs on the board.
"There wasn't many occasions where Swann had four men around the bat. That's why you bat so long, to allow yourself periods with men around the bat."
However, Nasser Hussain, Vaughan's predecessor as England captain, had more sympathy for Cook and England coach Andy Flower.
"When it's your team you don't press G for gamble," Hussain said.
"Flower, (Andrew) Strauss (England's most recent ex-captain) and Cook, they've been successful by first being cautious, is there any surprise at what's happened in this Test match?"
Had rain denied England victory, Cook's seemingly excessive caution would have come under greater scrutiny.
But the 28-year-old opener, who at Headingley became the first England batsman to score 25 Test hundreds courtesy of a second innings 130, had no trouble justifying his approach after New Zealand were bowled out for 220, with the final four wickets falling inside 22 overs.
"I think the result vindicates the decisions. There is no doubt about that at all," Cook said.
"You are judged as a captain on results. In this game we have won by 250 runs. We were 1-0 up in the series and we did not want to give them a sniff in the series because wins don't come round very easily or very often."