Simpson, 70, who will later Monday be inducted into Cricket Australia's Hall of Fame, has criticised contemporary coaches' methods.
The former Test skipper said coaches should spend less time behind the laptop analysing statistics and more time developing players' ability.
Simpson was appointed Australia's first full-time coach two decades ago and his ability to transform a struggling cricket nation to a World-Cup winning side within a couple of years was credited as the start of Australia's resurgence as a power.
Although a fan of using video analysis for reviewing players' techniques, Simpson questioned the effectiveness of computer analysis over the game itself.
"We've got all the computers and we've got everything like that and you'd think that you'd get your fielding positions perfect wouldn't you?," Simpson said Monday.
"You should know where the ball is. Why do we have two men behind square leg? Why do we have no one at third man for so long when something like 25-30 percent of all runs are scored at third man?"
But Buchanan, a former university lecturer who guided Australia to a successful World Cup defence in 2003 and kept the side on top of the Test rankings, hit back at Simpson's criticism.
"I think sometimes people make comments out of ignorance," Buchanan told Australian Associated Press.
"I really just think people don't understand what the role of the coach is now," he said.
"It's evolving with new technology. It doesn't mean what was done before was wrong.
"For those people who choose to criticise they should spend some time with the team and try to come to terms with what's required."
Buchanan, 52, said the Australian Cricket Board (now Cricket Australia) desperately needed a mentor to put Allan Border's young side "back on the right path" in the mid-1980s.
"They found in Bobby Simpson the right person to do that," he said.
"He was Australia's first coach and basically got Australian cricket back on track and I think that was a major achievement.
"He should be praised because he established the role."
Buchanan was last October re-appointed as the Australian team coach through to after next year's World Cup in the West Indies.
Buchanan's contract with CA was due to expire amid raging debate over his influence on the Australian team during last year's 2-1 Ashes series loss to England.
One of Buchanan's fiercest critics has been former Australian Test captain and now television commentator Ian Chappell, who urged skipper Ricky Ponting to seek guidance from senior players rather than Buchanan.