"It'll be just a little bit more icing on the cake. The cake's been well made for a long period of time, and there's a lot of icing on it," Bennett said.
Just the second man in history to represent Australia in rugby league and New Zealand in rugby union, Mosgiel-born Thorn has also won State of Origin matches with Queensland and titles with the Brisbane Broncos in league, and with Canterbury and the Crusaders in union.
"He's quite simply a winner," Bennett said.
"Everybody wants to play with him - that's the greatest compliment you can get. There's nothing he hasn't done. I don't know anyone that has done what he's done."
Crusaders coach and former team-mate Todd Blackadder called Thorn the "ultimate competitor".
"He could easily have retired a few years ago and sat back and think he's achieved enough. But he hasn't. If the All Blacks win (the World Cup), this will be a fitting pinnacle to Brad's career."
Michael Hagan, who also coached Thorn in State of Origin for Queensland, said the fact Thorn had switched codes had not affected how people viewed him.
"I doubt the more genuine sporting fans would have anything other than admiration for what he's achieved in both codes."
League fans who followed Thorn's career in Australia would be more than happy to see him "finish in the appropriate way" with the All Blacks, Hagan said.
"I'm sure he will have a pretty big influence on the outcome."
Hagan said Thorn was at the top of his game when he coached him around 2005 "and he's still at the top of his game now".
"I think that's probably the thing about him. He's been very professional and very consistent for such a long time."
Blackadder said Thorn's history of success meant "he knows what it takes to win".
"You just can't beat that type of experience. And for the other guys too, he will be giving them a lot of self-belief. I think the most important things is that he's just so hungry and that desire's there."
Hagan said Thorn should be recognised as a great ambassador for both codes "on both sides of the ditch".
