BTW would Soviet Artillery Breaktrough divisions be implemented in game? If yes, will they be a unit like any other or show up as indipendent unit?
Artillery divisions showing up as independent units attachable to HQ's would be interesting, as that would mean you could attach around 240 guns and around 50 mortars to a HQ/Corps as a single attachment. That would make the people using pre-patch WitP:AE artillery deathstars blush.
Yes, they are in the game and they are represented on the map like other divisions.
Can they be combined into corps as they were historically from time to time?
Also: how are artillery divisions formed? By combining a number of existing artillery regiments/brigades into a greater whole?
Artillery being such a crucial asset for the Soviets, the system of combining smaller artillery units into bigger ones could cut down on a lot of micromanagement whilst also giving the Soviet player more strategic support options.