O'Sullivan notes that during the slump farmers needed "leadership from the co-op."
"The co-op gave a certain amount of ... pastoral care in the sense of making funds available to help its shareholders through those difficult times when the pay-out wasn't covering their outgoings."
Mackay questions whether Wilson's legacy has been tainted by Chief Executive Theo Spierings, who he says is not as personable.
"I think everybody who has been involved in Fonterra to some degree has a tainted legacy," says O'Sullivan, "[and] some of that is the result of events."
Another big issue facing Fonterra is its relationship with the Government says O'Sullivan.
"The Government [is] thinking quite carefully about whether the structure for Fonterra is the right one and that will be something which the Government [will be] waiting to see what comes out of the various inquiries and reports."
Existing director John Monaghan will be the new chairman and O'Sullivan says his recent article on the Dairy Industry Restructuring Act (DIRA) was "written with great clarity."
"You were in no doubt about what his thoughts were on this [DIRA] and that would be welcome."