Marshall is already the main playmaker for the Kiwis, one of the best attacking threats and the goalkicker. Could captaincy could become a burden, especially with the off-field demands that go with the job?
"I wouldn't agree that it is a major distraction for Benji to have the captaincy and be the five-eighth and goalkicker at the same time," says Sheens. "Most of the goalkickers come from within the spine too and Benji's [kicking] figures have been in the top six this year so that has been one of the strengths of his game.
"The big issue you have to be careful about as a captain is that you don't become a traffic cop," adds Sheens. "By that, I mean you start worrying about what everyone else is doing and don't have the same impact with your own game. I haven't seen evidence of that at club level but I am not associated with the Kiwis directly at test level so I am not sure how he handles that. That would be a question for Stephen Kearney."
It certainly is a debate for Kearney, Marshall and the Kiwis' brains trust.
Marshall is a highly respected leader within the group and has been an ever-present since first becoming captain in 2009. He is also on the cusp of claiming the record for most tests as Kiwis' skipper, as he will equal Gary Freeman's record (19 matches) next week in Townsville.
But since hitting fantastic heights in the 2010 Four Nations Final when he was the major catalyst for an incredible New Zealand comeback (he was also prominent during the credible 2009 campaign), Marshall's star has only occasionally flickered at test level. He was ineffective in the Anzac test earlier this year and part of a dismal, injury-hit tour to Great Britain at the end of last year.
Ahead of next year's World Cup, if Kearney is to make a change it will need to be soon. He has options, with Simon Mannering and Jeremy Smith the most obvious and Kieran Foran probably a left-field contender. Traditionally, the Kiwis have often prospered with leaders from the pack; think of Graeme West, Mark Graham, Hugh McGahan, Ruben Wiki and Nathan Cayless.
Not many teams in world sport are better at pouncing on and punishing errors than the Kangaroos.
Marshall plays the game on the edge - and is at his best when he takes chances - but that also brings the probability of errors, a difficult situation for a captain.
"It is a tricky one," says McGahan. "On the field, the captain steps in when things are going wrong and there needs to be changes.
"The problem for Benji is his fortunes are so closely aligned with the team.
"Generally, if things are going wrong it is because it is not going right for him - which then makes it hard for him to tell everyone to lift. He can't do that if things aren't going well for him as a player."
McGahan added that he is not advocating that Marshall should be removed as captain but wonders how it might be affecting his game.
"You don't want a guy like him to start to play more conservatively because he is captain," says McGahan. "He is at his best when he is running on instinct."
"Benji's had an up and down year at the Tigers," admits Kearney. "It's been a bit of a rollercoaster for him but as far as I am concerned, he is is still the best man for the job. He enjoys the responsibility and is our leader."