I'm pretty sure that part of the decision of keeping the linear board mechanic in subsequent Mario Party games is to streamline the whole gameplay by cutting some unnecessary waiting for the others to take their decision and lessen the complexity for the more inexperienced players to join the fun. Although this does cut a lot of strategy by considerably limiting your control of the situation, there are some people who are just simply there for the mini-games and don't like waiting for too long. The same can be said for amiibo party as well when it comes to the board design.
Mario Party is now a franchise that is going to cater to the less experienced players, so it's not surprising to see the strategy element taking backseat priority-wise.