As in, an object that requires a specific weapon to be destroyed? Well, Fish is playing around with an elemental damage system at the moment, so I'd say it's probable that he'll implement enemies that are weak to certain kinds of damage (and, if logic follows, he could make things like "ice crates" that are impervious to everything other than fire weapons). I support the idea of having to go out of your way to get and keep certain weapons for certain situations, especially now that there is an inventory system.
Oh, and I'd be down for there being random structures in the wilderness made entirely out of crates that act like 3-d mazes. At the center of the maze is a really good weapon, but each crate contains several super powerful enemies to discourage just destroying the crate maze to get to the center. You can still do that if you want to, and if you wanted to get Juice destroying the maze would be very lucrative. I guess that kinda goes along the lines of "hiding things behind crates," but I don't know exactly what you mean.