The use of nominated school staff and peer assessors on Estyn teams has made the inspection process "more human", according to teachers.
Nominees - school staff members nominated to work with inspectors - represent an important bridge between a school and their Estyn team, according to an evaluation of the agency's new inspection framework, introduced two years ago.
Other 2004 innovations, such as self-evaluation and the use of peer assessors in schools, are also having a positive effect, says the evaluation report.
Peer assessors are teachers who have undergone Estyn training and take part in inspections of other schools. The aim is to bring a teacher perspective to the process, but only a few of the schools interviewed for the report had had one.
Rufus Evans, headteacher at Bryn primary school in Llanelli, Carmarthenshire, was inspected in March. He felt the presence of a nominee had enhanced the process because it meant the school had a voice. But he was not so convinced of the value of peer assessors.
"It means there's an extra body in the school that you don't necessarily want. I question the motives of some. Is it a way for them to be noticed, if they want to become inspectors themselves?
"But it was less stressful in terms of the attitudes of the inspectors. We felt they were more approachable."
The evaluation findings were based on interviews with a sample of inspectors and people working in education. Responses were also gleaned from a workshop session with representatives from three school inspection forums.
The report, compiled by accountancy firm PricewaterhouseCoopers, found the use of nominees was "extremely beneficial".
Respondents said they encouraged the inspection team to focus on issues that schools considered important, could explain to their colleagues key details about the inspection, and make the inspection "more transparent".
The introduction of peer assessors was also praised. Their presence was said to bring credibility and knowledge of current practice. And there was a "clear enthusiasm" for self-evaluation.
The report said: "Inspectors stated that self-evaluation was making providers think more vigorously and in a more structured, self-critical manner about the effectiveness of their service."
But the report also found that extra guidance was sometimes required to help schools with self-evaluation. They also needed more help with their official response to Estyn's findings. The agency wants to provide a tightly structured template and publish good examples.
Michael Doyle, head at Heolddu comprehensive in Bargoed, Caerphilly, endorsed the idea of peer assessors but felt their presence could be a disadvantage if they came from a different educational background.
Mr Doyle also welcomed the prospect of more guidance for self-evaluation, describing the process as a "double-edged sword".
"You're encouraged to be honest and critical, but if you're too critical and score yourself a three, they seldom put it up to two."
Evaluation of inspection arrangements, see www.estyn.gov.uk