I agree with you, because even the director said that one of the things that were out of the overall historical sense was the fact that Moana would be a chief. The fact alone that she became one, it would mean that she is strong enough to rule. But as you can see she is respected by the whole Motu Nui people. So much that they left the island to find another places, starting a new era.Matriarchal is the word and yes, but only in certain facets of society. Women are revered and respected but only for the things they are good at (i.e Child rearing, cooking, farming, etc). When it came to war and decisions on the tribe as a whole, it came down to Chief's which were predominately male. Obviously she would have to take a husband to keep her line going which means her husband would rule.
John Musker and Ron Clements even said they didn't name the island after a real name to don't annul other cultures where the women ARE revered as capable leaders. Not all the tribes, cultures and society in Polynesia are sexist y'know. I know that because I am part of that culture too.