The problem with that is you will have to figure out a way for the AI to adapt to whatever the human managers throws at it and I don't think they are anyway near there yet. I know nothing about game development however, my guess is that the reason why we still have structured formations is mainly to give the AI points of references so even if you give roles that change the movement a bit the AI still roughly knows where players will end up. If you look at asymmetric formations for example, the reason they can be very successful is because they break that structure for the AI because you will have players making movements and ending up in positions where they shouldn't really be.
I would love a more fluid system if they could find a way to make it work but before they implement that I want them to give us a way to set up how we want to press, it still feels a bit random at the moment and the players don't do it as a unit if you go and watch any of the tactical videos on the coaches voice YouTube channel you will find out that we can't do most of what the managers talk about.