Despite the fact that Widmore told Locke "there is a war coming, and if you're not there, the wrong side will win," the only character in the series that suggested the Oceanic 6 actually bring Locke's corpse back to the Island was Eloise. Though I won't in this blog comment on my issues with her character as whole, it's worth noting that she seemed to know what she was doing regarding getting everyone back the Island via Ajira 316.
The question is -- was the fact that Locke's body served as a vessel for Man in Black and the completion of his "loophole" something that Eloise knew about, considered, and helped orchestrate? Or was that simply a terrible consequence that she did not see coming?
Perhaps this ties into the thought floating around that Ben was unwittingly the pawn of Smokey all along. From a dramatic sense, the fact that Ben paves the way for Smokey's vessel, which in turns, Smokey uses to convince him to turn around and kill Jacob, works pretty well. Maybe Eloise really just wanted to recreated the events of 815 as much as she possibly could and believed that Locke would serve as a "proxy" for Christian.
But then again, what was Christian's purpose on the Island? For his body and/or image to be used by Man in Black to manipulate the LOSTies into eventually killing Jacob, right? So if Locke's body is a proxy for Christian's body, does that perhaps suggest that Eloise was on Team Smokey?