It's the most talented squad Wales have had since professional rugby started
Former captain Gareth Llewellyn says Wales are underachieving under present coach Warren Gatland.
New Zealander Gatland made a huge impression when he took the job, taking on Wales' 2007 World Cup flops and leading them to the 2008 Grand Slam.
Wales were a competitive fourth in last year's Six Nations, but struggled to just two wins this year.
"We have to drastically change the structure we are playing under," said Llewellyn, who won 92 caps for Wales.
"We're not giving our guys the best chance to use the talent they've got."
Wales have a history of sacking coaches in the build-ups to World Cups and - although criticism of Gatland has grown over the past two seasons - pundits have been generally positive in their treatment of the Kiwi.
But former second-row Llewellyn - who played for Wales in three World Cups and was his country's leading cap holder before being overtaken by Gareth Thomas, Colin Charvis and Martyn Williams - says Gatland is not getting the most out of a talented squad.
For me the biggest question in that squad is over Warren at the moment
"For me the biggest question in that squad is over Warren at the moment," Llewellyn, 41, said on BBC Wales' Scrum V rugby programme.
"We've got to come up with something else which is going to give us a bit of diversity in the way we play.
"Warren's success is built on playing the game a certain way. When he was coach of Wasps it was built on a fantastic pack and a team that was much better than anything else out there.
"He played a particular system that worked and he's carried that on.
"Watching Wales is like watching Wasps when I used to play against them," added Llewellyn, who played for Llanharan, Neath, Harlequins, Ospreys, Narbonne and Bristol in a well-travelled career.
"But Wales are not that much better man-for-man than anyone else, so they have to do something else.
"We're not going to go to the southern hemisphere and overrun Australia, South Africa and New Zealand so we have to develop our game more."
Gatland has promised to test his side against the best as they build to next year's World Cup in New Zealand.
Wales' next challenge is against world champions South Africa in Cardiff on 5 June, before they face a daunting two-Test tour of New Zealand.
In the autumn series at the Millennium Stadium they again meet the All Blacks and Springboks, along with Australia and 2007 World Cup bogey team Fiji.
Gareth Llewellyn won 94 caps in a well-travelled career
Of those seven fixtures a victory over Fiji is the only one Wales should be confident of, but if they lose the others pressure is sure to mount on Gatland.
"We have got the players to compete," insisted Llewellyn. "But we have to develop our game, what Warren has built his success on is not going to sustain us at international level.
"We've probably got the best set of players any Welsh coach has ever had, but relative to the opposition we're not that much better than anyone else.
"We play in bursts, when we get desperate and think the game's gone away from us and we start having to play more.
"That's more down to individuals than what they practice [with the coaches].
"But we have more potential than in previous World Cups because we have better players, the most talented squad Wales have had since professional rugby started."