One thing that I find on these screenshots are that ships seems to be the equivalent of a land brigade now. Each naval task force will be the same as a land division or so it seams. This will make things easier I presume on the player and fixes the stacking issues. It also pretty much tells us that brigades will be interchangeable between divisions, at least it is possible for ships and planes.
I also gather that an air wing (or what each smallest unit will be called) will also be a brigade that you attach to a division (unit). These will then operate together as a stack did in HoI2, at least this is my logical conclusion.
You build capital ships on the Production screen and these can appear on the map on their own, so they are the basic naval unit. But unlike the basic ground unit, ships and air wings are designated at the Brigade level "X", rather than Division "XX". In naval terms a Division is always a small group of ships, something like 4-6 cruisers, or a couple of capital ships, and is therefore roughly the equivalent of the ground Corps.
The fact that you can remove a Naval Brigade (a ship) from a Naval Division (a group of ships), does not at all prove that you can remove ground unit Brigades from ground unit Divisions. Ground unit Brigades are building blocks within the ground unit Divisions and are not capable of separate existence, and appearing on the map.