Okay, I have an idea, don't know what it worth... probably 2 cents.
One of the things that did not work for many people in ROTS is the way too quick turning of Anakin to the dark side. Now, if we can make more obivious to the audience that Palpatine is the "creator" of Anakin, maybe through midichlorians manipulations (I know Ady said: 'no midichlorians!"), we could somehow show that the order 66 has an effect on him too...
I told you... probably 2 cents.