I really, really want to like the new system, as someone who used both field marshals and generals in equal measure in the old game. I kind of like how the game mechanics now encourage 40 width divisions (because a general can either command 24 1-width divisions, or 24 40-width divisions, so might as well go 40) but it seems so buggy at the moment. On defense, it's fine, but it falls to pieces for me on the offensive. For one, assigning a field marshal to a front divides armies up along the front line. This is despite the fact that the new general upgrade trees encourage having specialized armies. This means that my panzer leader ends up assigned to a section of the front without infantry support, while my infantry lacks armour. And the front width varies as the offensive progresses. I've had whole armies cram onto one tile because other armies gradually expanded into their assigned area of the front. The problem is compounded if allies are on your frontline, because they don't adhere to your pre-planned offensives. Additionally, armies sometimes detach from a frontline, usually when done eradicating a pocket, and don't automatically reassign. Half the time I can't simply ctrl+right click them back into line, I surmise due to bugs.
I loved this kind of mechanic in HoI 3, but it worked there because you could pre-set where you wanted each given army group to attack by painting the map (similar to how the garrison tool works now). I really want the new mechanics to be as fun as they possibly can be, but as it stands I would rather end a game than open up more than one front at a time, because I have to micromanage them so much.