I'm cribbing from myself here, but here are some additional thoughts of mine from another thread:
http://originaltrilogy.com/forum/topic.cfm/STAR-WARS-Movies-Animated/post/403117/#TopicPost403117
In trying to craft a "realistic and satisfactory" arc for Anakin that includes a "fall/seduction" to the Dark Side... I've analized Luke's "lean to the Dark Side" at the end of Jedi. It's the only concrete example of how the Dark Side can overtake an otherwise good Jedi. And the conclusion I've come to is that the scene, on the surface, is broken to me. Palpatine claims Luke will be his new apprentice if he can take out Vader. Assuming this is true, why would Luke "stop killing the bad guys" if the Dark Side had compelled him to kill Vader? Wouldn't he follow through and take out Palpatine as well? He would have tried, at least, right? Either he would have killed Palpatine or would have been killed by Palpatine. Maybe I can see him attacking Palpatine and being toyed with Cat->Mouse until Palpatine traps him and takes him prisoner for further indoctrination...
But I digress. My point is this: Palpatine appears to not have a very good exit strategy from DSII at the end of RotJ. This makes him look a little stupid. And how exactly Luke would end up being his apprentice in any scenario- I can't see it working out. IF you take into account Palpatine using cloning and not fearing his own death... then he is poised to use his death as a means of converting Luke to the Dark Side. If Luke wins his "duel" with Vader by tapping into the Dark Side, presumably he then turns on an undefended Palpatine. The Light Side would not allow Luke to kill an undefended man, no matter how evil he might be. But the Dark Side! The Dark Side would compel Luke to take revenge on the man, to blame him for the making Luke kill his own father! It was Palpatine's fault for corrupting him afterall! So, Luke cuts him down! Is his Journey to the Dark Side complete? No, what nonsense! But his Journey to the Dark Side has begun. And Palpatine, having cheated death, will be there to guide him in.
Anakin's first temptation as a Sith should not have been to murder innocent Jedi children. Murder. Innocent. Jedi. Children. It goes against everything the man stood for 10 minutes prior. Sending him to despose of the Separatist Leaders is much better. It's not murder, it's a military assassination to end a war. Palpatine is a commander and Anakin is a soldier- and the war does need to end. So you can justify it, from a moral perspective. And using the Dark Side to control enough power to bring to pass a good thing... THAT is a temptation for a Jedi.