I may have not played JWE2 myself yet, but I've seen some objects that are featured in Campaign and Chaos Theory modes that are exclusive to certain levels and mission objectives.
Fallen logs and dead deer when tracking an Allosaurus and the T.Rex in Campaign and Chaos Theory respectively. And the burnt up tree groves in the Scorched Earth level of the Biosyn campaign. Though they are objects in the game, they aren't things you can place yourself.
Since there are plenty of objects you can place in Sandbox mode, such as the recently added DFW protection structures from the Dominion Chaos Theory game, how about those things as well?
Fallen logs and dead deer when tracking an Allosaurus and the T.Rex in Campaign and Chaos Theory respectively. And the burnt up tree groves in the Scorched Earth level of the Biosyn campaign. Though they are objects in the game, they aren't things you can place yourself.
Since there are plenty of objects you can place in Sandbox mode, such as the recently added DFW protection structures from the Dominion Chaos Theory game, how about those things as well?