The 34-year-old bowed out by claiming his 58th touchdown in a Wales shirt - an ongoing record - during the 21-18 World Cup bronze-medal match defeat against Australia on Friday.
And Williams' favourite rugby stage - the Millennium Stadium - now looks likely to witness him step down as an international player when the Wallabies arrive in Cardiff for a friendly on December 3.
Williams has given several strong hints this season will be his last as a Test match performer - a level he has graced since 2000 - and the homecoming for Wales' World Cup heroes would appear a perfect swansong.
"It has been incredible to play alongside Shane," Wales centre Roberts said.
"I grew up watching him as a kid. He is an absolute legend of a bloke, and hopefully he will get to run out at the Millennium Stadium against Australia in December.
"I am disappointed for him that we finished the World Cup in the fashion we did. He's been magnificent this tournament - he's certainly a player I think everyone in world rugby admires.
"If anyone deserves it (a Millennium Stadium farewell), it's him.
"The input he has made to Welsh rugby over the last 13 or 14 years is unparalleled. He is probably the most exciting player of his generation, and he is an incredible man.
"We would love him to continue. He's a pretty special player, but it is whatever he decides to do - it's ultimately his decision.
"Whatever he decides to do, he will have the respect of the rugby world."
Roberts, meanwhile, was left to contemplate another narrow defeat during a tournament when Wales will reflect on losses against the Wallabies, South Africa and France by a combined total of only five points.
"To lose to South Africa by a point, France by a point and Australia by three, it just goes to show the fine lines at this level," he added.
"Yes, we would have preferred to be playing on Sunday (in the final), but when you pull on the Welsh shirt at Eden Park, there is no doubt our boys were up for that game.
"We went in at half-time 7-3 down, but we were obviously still in the game. We clawed our way back, but we missed a few crucial kicks at goal.
"It's such fine lines at this level - one pass here, one kick there, a missed tackle here. Little moments in games count.
"I remember the 2009 Lions (they lost the Test series to South Africa 2-1), and I remember a semi-final of the Heineken Cup a few years ago with the (Cardiff) Blues that went to a penalty shoot-out.
"These last two weeks have been pretty brutal. It's a rollercoaster of emotions, I suppose."
Roberts, though, delivered an upbeat assessment as Wales prepare for the journey home on Saturday, before reassembling to meet Australia in six weeks' time and then facing a Six Nations campaign that will probably see them installed as title favourites.
"We will go away with a feeling that we can compete with the best in world rugby," he said.
"That is a mindset to take into the match against Australia in December, the forthcoming Six Nations, the tour to Australia next summer and the next couple of years.
"If we get things right, we will put teams like this away. We made too many simple errors tonight, and at this level, errors like that will lose you games. There are no excuses.
"We haven't beaten a southern hemisphere team down here, so that is the disappointing thing. Our next opportunity to do that comes next summer.
"To go from the elation of that Ireland (quarter-final) victory to events of the last two weeks has been emotionally very tough, but that is the fine line at this level.
"We need to take it on the chin and move forward."
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