Mr Millar, who announced this week that Health Minister Tony Ryall would not be reappointing him, said he could see the need for an increase in regional and national planning.
However, if regional and national decision-making went too far, it could be asked "what is the point of going through a quite expensive process of electing people" who then had very little authority.
There was also not likely to be much enthusiasm for serving on boards if people felt they were there as puppets.
Asked about his relationship with Mr Ryall and suggestions the minister tended to "micro-manage", Mr Millar said they had a perfectly reasonable working relationship, occasionally agreeing to disagree.
He had expected to have a lot of interaction with Mr Ryall and was aware the minister's style was to keep in contact with many people in the sector.
In any situation where there were issues involving the line between governance and management, this sort of contact could have mixed results.
It could be useful as a way of validating information from a variety of sources, but there was also a risk it could "get in the road" of effective decision-making if people were encouraged to short-circuit already established proper processes.
"It's one of those things which needs to be kept in balance a bit."
Mr Ryall did not respond to questions about his style, but in an email statement he said regional collaboration and planning at a national level did have an element of reduced autonomy. However, this could also be read as opening tightly closed management circles.
For too long, some boards had been claiming autonomy as a reason for not working together collaboratively, he said.
