Hrm, I think I can provide my two cents.
[*]In A New Hope, Kenobi refers to the Jedi purges by saying that Vader hunted down the Jedi. In Revenge Of The Sith, though, we instead see the Jedi being all killed simultaneously by clone troopers (which begs the question, how do these guys go down so fast; are they Jedi or are't they?). This can be explained, however, by having a large number of Jedi that aren't on the front lines be considered to have survived all across the galaxy -- again, this is not actually indicated.
Well, Jedi or not - they were all taken by surprise and were clearly outnumbered, you can't really do much when the numbers are totally against and you're surprised, though Yoda was the only one who had any idea, plus he had the 'good relations with the Wookies' and the fact that he's tiny help him. Either way, Vader must have killed some Jedi in the temple along with the Younglings (someone must have been watching over them), and I think its implied that there are a few more Jedi left to purge.
[*]At the end of Revenge Of The Sith, roughly 20 years before A New Hope, we see the beginning of the construction of the Death Star, which is presumably a 20 year venture. However, a larger Death Star is halfway completed after the ONE YEAR between The Empire Strikes Back and Return Of The Jedi.
Well, in Return of the Jedi the commander 'does' tell Vader that the Emperor is 'demanding the impossible' and that he 'needs more men'- now we know just how impossible it is, considering that the first one took 18 years to build. Even then, the Death Star is far from finished and still pretty rough looking. I don't know, I don't think thats farfetched.
[*]By the way, am I supposed to buy that the Clone Troopers become the Stormtroopers when a) they suddenly stop sounding like clones; and b) their ability to successfully operate their firearms suddenly drops so low that they would be more successful if they armed themselves with safety pins?
Maybe they cloned other people, other than Jango Fett. Don't forget, the original was killed in Attack of the Clones, and, sooner or later over the course of two decades they would have run out of clones and would need others - or maybe they just gave up on clones altogether, though, as you said, they should have stuck with them, considering their aim in the original trilogy.
[*]How is Darth Vader able to sense Kenobi on the Death Star, yet is seemingly unable to do the same on that volcanic planet? Is he really that far away? Of course, the question of Darth Vader's ability to sense things that should be obvious has been questioned since 1980 and 1983 (Luke the son and Leia the daughter, respectively).
As some have already stated, the ability to sense really does depend on the force and your ability at the time. i.e. - when the dark side of the force is powerful only the dark side can be tapped into, and other force users can't use the force as effectively - hence the lack of the Jedi's ability to even sense that the dark side was right under their very noses in the prequel trilogy. It could be argued that on Mustarfar, Vader's power with the dark side had not grown enough in order for him to sense everything - he had just turned from the 'light side' of the Force and was 'just' starting using his powers. Remember the Emperor saying that 'go to Mustarfar and kill the Viceroy, only then will you be powerful enough with the dark side'. Whehter he's lying or now, it is clear that Vader still has to continue growing with the dark side, and that takes time. On Mustarfar, the force is quite clearly with Obi-Wan (he wins) and he does, indeed, have the higher ground - Vader's abilities are less than his, in this moment.
[*]Anyone figure out yet why Owen Lars hates Obi-Wan Kenobi so much? It was one thing when we asumed that Anakin Skywalker and Owen actually knew each other for a significant period of time, but as they obviously did not, I find this somewhat mystifying.
I'm just reading the screenplay now and I don't really see Owen Lars hating Obi-Wan, though he probably is prejudiced against the Jedi, equating them with the failure of the Republic etc. Plus, he's on Tatooine, so what does he know? I find it curious that at the end of 'Revenge', its only Beru who greets Obi-Wan and Owen stands away. This distance could be interpreted as some resentment. Either way, his behaviour in 'A New Hope' seems to denote a very fatherly concern; being a Jedi did your father no favours and I don't want you running off becoming one.
[*]As hard to believe the duel was between Kenobi and Vader in A New Hope was before, how can I honestly believe it after having seen the same two duel in Revenge Of The Sith?
Kenobi's powers were, after all, weak during that one. Plus, Kenobi had a plan of what to do, anyway - he wanted to sacrifice himself, which explains why his moves are more defensive (i.e. stalling until Luke gets there) rather than oofensive. Also, by then Vader is more powerful with the dark side and hence more powerful in general, and was really just taunting Obi-Wan. Incidentally, people can say all they want about the Prequel fight sequences and how splendid they are (they are), for me, no fight is as cool as the one between Luke and Vader in 'Jedi'.
[*]How in the world does Palpatine's lighting so terribly disfigure himself in Revenge Of The Sith, while Luke walks away unscathed in Return Of The Jedi?
Thats a good one. I think the difference could be that in Jedi he's frying Luke at a distance and not necessarily aiming at his face, while in Sith his lightning is engulfing his face entirely as Windu's lightsabre is pretty much right next to him. Also, I think its a combination of things; its the lightning but its also the fact that his control of the dark side is becoming almost too great for him to contain, and it is ravaging his body. This is not entirely unsubstantiated, notice how his voice is given this terrifying bass and ghastly animal sounds immediately after frying Mace Windu - that is the sound of his body being totally consumed by the dark side; he is at the height of his powers here, and his body is paying the price for it.
Ant.