Clinical Ireland eye Wales scalp to continue perfect Six Nations start
The Irish sit atop the table after two bonus points wins and welcome an inexperienced Wales side, who have gone down to narrow defeats against Scotland and England.
MacNeill, who was an integral part of the Ireland side that won the Triple Crown in 1982 and 1985, says the Irish have a spring in their step as they appear to have resolved the issues that hung over them coming into the tournament.
Namely, head coach Andy Farrell has succeeded in moving them on from their "shattering" Rugby World Cup quarter-final loss to New Zealand.
Perhaps, though, the major issue laid to rest, according to MacNeill, is the manner in which fly-half Jack Crowley has fitted into the huge vacuum left by the now-retired Johnny Sexton.
"With regard to Crowley and Sexton that was a huge issue," said MacNeill.
"There was so much chat before the Six Nations, there has never been such a debate over replacing one player in the Ireland side.
"So much more than any of the talk when other legends retired like Brian O'Driscoll and Paul O'Connell."
Crowley, 24, has been at the heart of Ireland's stunning start to the tournament.
First came a sublime 38-17 victory over the French in Marseille, a record away win in France. Then followed a 36-0 thrashing of Italy, the first time they had blanked Six Nations opposition since a 17-0 victory over England in 1987.
Crowley marked the Italy game with his first try for his country.
"Fair dues to him he has done well," said MacNeill. "Now people are going to matches looking forward to seeing him play."
'Proving people wrong'
With Crowley settled, MacNeill says the rest of the team have been comfortable in their skin and does not think the Welsh will put them off their stride.
"Ireland have got on with the job, moved on from last October and to hold Italy to nil as they did is no mean feat, not many teams do that these days," said the 65-year-old.
MacNeill's main concern for the Welsh is that with so many veterans gone post the World Cup where is "the leadership" going to come from if things go badly awry early on in Dublin?
His pessimism is matched by former Welsh stars, Shane Williams saying he fears what might happen.
However, Alix Popham is not of that mindset, the former backrow forward, a member of Wales' 2008 title-winning side, strikes a more upbeat note based on what he has seen so far.
"Yes, there is hope, if not of a win at least a fight, a close one, that is all one can ask for," he told AFP.
"If they can build on the last two performances, especially the second-half against the Scots (they lost 27-26 after trailing 27-0) and for a very young squad to go to Twickenham and almost come away with a win (they lost 17-14) is a positive."
Popham, 44, says there is nothing more the Welsh savour than being regarded as cannon fodder.
"We love being the underdog and proving people wrong," he said.
Popham says the task facing head coach Warren Gatland ahead of the tournament in replacing players had been more taxing than that of opposite number Andy Farrell, who really just had one to replace, Sexton, "albeit a legend".
"I am a positive person and what I have seen has overall been positive with a young squad," he said.
"The only way they can develop is to be put out there into the Colosseum."