A couple of points ...
Orr was always in shape. He made enough money that he stayed in shape over the Summers ..... Bobby always arrived to camp ready to go.
Sanderson had cooled-off somewhat (on-ice anyway ...) by 1972 - compared to the 1968-70 period. That doesn't suggest he wasn't unpredictable in a melee however.
I saw Sanderson play in person many times with my Dad at MLGs in the 1970's (Bruins, Rangers, and Pens) and he was just an unbelieveable defensive centreman. That skill-set would have been invaluable to Team Cannada '72.
As we know, Sinden was the Coach and Sanderson had just helped the Bruins win the second Cup in May, 1972 - so he clearly would have been on the team.
Cheevers was at his peak in 1972 - although he would play well until 1980.
Hull is a legend and the Olympic Ice Surface was tailor-made for him. Imagine a 33 year-old Hull with space ! Imagine Tretiak getting one by the ears early from Hull .... this alone could have changed the psychology of the series !
JC Tremblay, Serge Savard, Guy Lapointe, Brad Park and Bobby Orr on D ! This again changes the series to Canada's favour.
Bobby Orr is the largest factor. Orr would not have allowed the Game One loss. And when he got to Russia on the large ice-surface, it would have been a different game altogether. The Orr of 1969 to 1972 - before the very serious 1972 knee surgery - was the Orr of Legend. He was unstoppable back in that period.