As it looks they are going to ship the game with a map editor or release it short after, maybe already more customization like tuning unit stats for custom games etc.
So lets pretend it is as extensive as we would want it to and imagine what kind of great maps and modes we can built if they really take TW Warhammer as rolemodel.
I am imagining a asymmetrical Siege map with a "fortress" and several defense lines, massive turrets and various plateaus and obstacles that might shape up like walls and Different directions to attack from and circumvent defense points. Like generators for the turrets being placed in a "blind spot" that are hard to defend but also on hard to reach terrain. (Maybe even outside the fortress for no reason like in old scifi movies.) Only the defenders have a power core and the attackers are given a set amount of units and or time (until help arrives for the besieged.)