I'm personally going to point out that no episode of lost has ever made me feel these characters than this episode. The moment Richard told Sun that he watched everyone that lived on the island in 1977 DIE, I immediate felt a lump in my chest cause the fact that the most iconic characters on the show may kick the bucket just sent me in a whirlpool of sadness.
Follow The Leader really shows so many conflicts that are no doubt going to be resolved in the two part season finale. First off, Ben and Richard are seemingly teaming up to probably kill Locke again after Locke is hellbent on finally meeting Jacob. Next we have the conflict between the Dharma Initiative team from 1977 and Lafleur (sawyer) and the others who are lost in 1977. Last, we have a pretty dynamic conflict between Kate and Jack, with Kate for the first time ever NOT joining Jack on one of his heroic deeds (maybe heroic?). All I can say is that all of these conflict will end with very bad results, results that may shake the very fabric of the Island itself.
The episode certainly had the best twists i've seen in a while both tragic and shocking. First we have that chilling reminder from Richard being that whoever is in 1977 WILL DIE. Second, Future Locke being the one who told his Past self through richard that he has to die in order to "save" the island. Third being that Kate ran from Jack in order to be with Sawyer again, a fact that Juliet doesn't want anything to do with. Last we have the biggest cliffhanger as Locke fully explains his motives to Ben which detail that he never wanted to save the others from time, but to kill jacob and stop the island for good.
In the end, Follow The Leader is quite possibly the best Pre-season finale episode Lost has yet. It raises so many questions on what the conflicts mentioned may end, it alludes to what may happen in Season Six, and it does a damn great job for the hour of making sure that this season finale is going to blow everything out of proportion.
BTW: is it just me, or was it really nessacary to place a Hydrogen Bomb, THAT FAR into the Island?