Rob Howley is "Wales' most decorated coach" and will be a loss if he follows Robin McBryde to Irish rugby, says Martyn Williams.
McBryde has been appointed Leinster scrum coach, while Howley has been touted as Munster attack coach.
Williams wishes both coaches were kept within the Welsh system after the 2019 World Cup.
"If he [Howley] ends up in Munster it is great for them, not for the Welsh regions," said Williams.
The pair have been key members of Wales boss Warren Gatland's coaching team for more than a decade.
Howley has been Gatland's assistant in three Grand Slam triumphs and a British and Irish Lions 2013 series win in Australia and draw in New Zealand four years later.
The former Lions scrum-half was also acting head coach when Wales won the 2013 Six Nations title with Gatland on a sabbatical.
Munster attack coach Felix Jones will leave the province in June and Howley has reportedly had an interview with the Irish province.
"Ultimately he is the most decorated Welsh coach in the history of the game," said former Wales flanker Williams.
"You show me a Welsh coach who has a better CV than Rob Howley. You are judged on what you win, your trophies.
"Rob has been there and won Grand Slams and Six Nations Championships and been part of successful Lions tours.
"He has been an easy target and copped a bit of flak but he has come through all that."
Williams believes Welsh rugby cannot afford to lose Howley and McBryde with no Welsh permanent head coaches at any of the four regions.
"I still think it's a shame that we might be losing Robin and Rob," Williams told the Scrum V podcast.
"They should still be in the system in Wales and they are better than a lot of coaches that are in the system in Wales.
"All of the stuff they have learned and picked up, just to let that go across to Ireland, there has to be some way of keeping them involved.
"That is where our system falls down and it frustrates me.
"I played with and was coached by both of them. They have learned on the job because they did not have much coaching experience going into the international environment.
"But I understand if they want to get out of the goldfish bowl of Welsh rugby.
"They might be looking at wanting to go to Munster and Leinster because there is more chance of winning things there."
Wayne Pivac replaces Gatland as the new Wales boss after the World Cup with defence coach Shaun Edwards turning down a new contract as he prepares to join France from next year.