Here's an idea for those of you who take issue with Obi-Wan leaving Anakin to burn. Obi-Wan comes off as spiteful or at least merciless. We need a better reason for him to leave instead of going down and putting his friend out of his misery.
So I thought a good reason might be because he sees Palpatine's shuttle coming. In that moment, he knows Yoda is probably dead, the Republic is doomed, and he needs to high tail it out of there before he gets double teamed. His mission to kill Anakin is aborted, and his only goal is survival. Maybe at the very least he can prevent Padme and the kids from falling into the Emperor's hands.
It turns out there is a good place to put such a scene where Obi-Wan sees Palpatine's shuttle. Right before Anakin says, "This is the end for you my master." there is a pause in the fight as they stare at each other. See 5:47 here.. Here you could put in the shuttle flying over. Right after this shot, Obi-Wan makes his final stand and jumps over the river bank. It's a really good placement because it explains why Obi-Wan needs to end the fight quickly.
I don't know enough to do a mockup video, but here are some poorly photoshopped images of what I'm talking about.
After Anakin says, "This is the end for you my master." Cut to the shuttle landing, and then back to the ending of the duel. After Obi-Wan leaves, cut to Palpatine discovering Anakin's body.
Anyone think this is possible or worthwhile?