Hello! It would be nice to share your theories about Eko's murder by Smokie! I'm sure it has been already discussed before, but I wanted to come back to this.
It's hard to believe that Eko wasn't a candidate. He presented all the characteristics to remplace Jacob: he was lost in his life before the crash, Yemi's plane crashed on the same island as him (that reinforce the sense of destiny); and remember just how motivated he was to push the button in the bunker (that could make him a perfect protector of the light)... But, all right, let's admit that he wasn't a candidate for I don't know what reason...Why the hell The Man In Black needed to do this crazy manipulation, using Yemi's body in order to kill this cool priest? Couldn't he just savagely smash him on the trees, without doing this elaborate stuff with visions, as he simply did with Lapidus' fellow (and many others)?
Some may say that after Smokey's intervention, Eko stopped to be a candidate ...so do we have to assume that we stop to be candidates after refusing to confess? Hum...Jacob didn't seem that religious (and his little brother neither)!
It seems to me that at this point of the series, the writers had a whole different plan for the Monster and his purpose (but maybe it's just me). By the way, I know that the actor portraying Eko didn't want to stay in the series, so please don't use this argument to explain this element in the plot, I would like a good theory that fits with the story! Thanks in advance. (Sorry for imperfect english).