hello, since the game use very large terrains, it would be cool to have some ABC weapons (Atomic, Biological and Chemical) also known as WMDs.
Atomic weapons could be added as artillery shell, as bomb dropped by a military plane or as missile, fired from somewhere for example the main base when you call nuke support. it could be effective against a large area covered by enemies.
chemical weapons would be effective against infantry, can be also added as artillery shell, mortar shell or as helicopter/plane bomb. it would create a deadly smokecloud in that area, killing all who are inside the deadzone.
biological weapons like above but no smoke or anything, infantry would die slowly by sickness and could also spread, for example, when one soldier who was hit by biological weapon goes to soldiers who arent hit by biological weapon, he could spread his sickness to some or all of them.