The whole Deadman sequence was awesome, but that he got kicked out of his own body us amazing and interesting. It certainly implies something about either Deadman's possession ability, or the nature of the Black Lanterns. Or both.
Like, remember The Quiver? Why didn't Boston possess Ollie give the explanation of what a "quiver" is? Just to reduce the amount of exposition telephone? After all, he possesses Blood/Etrigan, the only one who actually knows what's going on. Or . . . maybe he couldn't. Maybe he can't possess a body that doesn't have a soul?