(Split off from the other thread)
So what were YOUR assumptions about the PT before you saw them. Here are some of my assumptions I made prior to seeing PT for the first time.
Jedi VS Sith
Prior to the PT, I assumed we were going to get a full on Jedi VS Sith battles during the clone wars, but on a grander scale. More like armies of sith clashing with armies of jedi in a Braveheart style battle. The closes things we actually got were not in the PT, but EU: cut scenes from The Old Republic MMO essentially were what I envisioned for the PT, long before that cut scene was created.
I assumed that the clone wars would have spanned the entire trilogy and we would have seen the war in full swing. Although we got that with TCW, the PT really only covered the very beginning and very end. Prior to the PT release, I had always assumed the clone wars had clones on both sides, possibly even cloned jedi and cloned sith (I can blame the Thrawn trilogy on that).
In the prequels, we didn't really get what I assumed we would. I assumed we would have seen more of a progression of Anakin being seduced by the dark side. Something more along the lines of Anakin being wreckless and angry, which we did get somewhat (killing the sand people is his first real step) but his turn in ROTS was more like a flipping a switch, than the culmination of him being tempted by the Emperor to turn to the dark side. I assumed he would have been secretly counciling Palpatine, or discovering the dark side on his own, because he was tempted by how much faster his power was attained by practicing the dark side. Killing the Sand People could have been a jumping off point for that, as he could have felt the power of the Dark Side for the first time, there. We sort of got Anakin counseling Palpatine in secret in ROTS, and it is implied that he did council Palpatine off screen in ROTS, but it would have been nice to see Palpatine actively poisoning Anakin and turning him against the jedi gradually, rather than the "gotta turn to the dark side if you wanna save Padme" angle.
I assumed we were going to see him in his late teens/early 20s from the start. Not 10 year old Anakin, until the TPM promos and previews came out. I had envisioned him a young adult who was gifted but untrained force wielder, and who was making a living as a spice freighter pilot, where Obi Wan discovered him, and took him under his wing.
One other thing I'd like to add about my assumption about Anakin prior to the PT, or at least prior to his turn was that we would actually see him hunting down jedi. We get that towards the end of ROTS, but I remember before ROTS came out (because we knew he would end up as Vader at some point), thinking it would have been cool if there was a masked new sith lord (wearing black robes like Maul, but wearing some sort of black mask like a ninja mask or sith helmet) who is seen killing jedi left and right. Obi Wan is dispatched to confront this new sith warrior, and during the battle, the sith is unmasked somehow, and revealed to be Anakin. I would have loved to see Obi Wan's horrified face during that reveal.
Obi Wan VS Anakin
As for the Obi Wan VS Anaklin duel, I suppose what we got was close enough to the ROTJ novelization. It works. But my assumption prior to the PT was that Anaklin and Obi Wan dueled at the top of a volcano, and Anakin was driven off a cliff and fell in, Mount Doom style.