Attackmove... this won't do. It works for attacking enemy units (anything that moves or can fire) but not for destroying structures in a base. I'm testing this with a team of different air units and the only buildings that will be destroyed are the result of splash damage when attacking units. When all units are killed the attacking air units are just idling above the enemies base until a new unit rolls out a war factory which will be attacked and killed immediatly.
Tried all kind of attack variations (Team Attack Move, Team Attack Hunt, Team Attack Player, etc.) all with the same "no structures" result.
The only possibility that worked (as far as I tried) is letting each single unit attack a building, all one by one. This won't do in the end because that way every single unit needs it's own attack script in where all possible buildings from all factions need to be defined.
Depending in what game mode I started the game, it only affected 1 of the 4 units and it was always the same one (forgot which one as I didn't look any further into this as it didn't do the job anyways).
Do they ignore buildings aswell in agressive stance, iirc you can set the production building to agressive stance and any unit that ventures from it will have that stance aswell?
As for the easy/hard thing. Could be that part of the scripting isnt working (right). iirc worldbuilder evolved out of the bfme engine and its possible some elements arent working anymore when it got repurposed for TW and KW. Or there are other prerequisites needed to get that part of the AI working.