In terms of the movie, I found Yoda's retreat from Palpatine a bit contrived. I know this is because Palpatine has to survive and Yoda has to go into hiding, but they could have dealt with it better than Yoda being pushed back/falling and then giving up.
Also, from my innocent layman's point of view, the movies, at least, really seemed to imply that the concentration level of the midichlorians was a factor in power levels. Perhaps not everything, but still a factor. Do these 'canon' books or other official sources actually say they are not? Just curious.