Yay! This is a ray of hope for the RPG. (And at least if it dies, they've started filling in the one real gap in stats/game mechanics in the game with Episode III). This is going to be very useful (my new campaign currently in planning is set in the Clone Wars, and going into the aftermath and rise of the Empire, so these will be very useful, those MagnaGuard stats are one thing I was explicitly wanting).
I find it interesting they completely re-did Palpatine's character build from Noble/Dark Side Devotee/Sith Acolyte/Sith Lord into Noble/Dark Side Marauder/Sith Warrior/Sith Lord after Episode III.
Yes, it's the level 20 cap issue. Yoda and the Emperor were both 20th level, Vader in the original trilogy was 18th. Of course, there is very little to stop you from making your own Epic level stats for the Emperor for the Rebellion era. The epic level rules work pretty cleanly for Star Wars (most of the Epic feats have got to go), Epic levels in just more abilty points, Vitality, the small epic rise in BAB and save, and more skill points would do fine (and the bonus feats).
I both love and hate the new Episode III Anakin stats. I like that they gave him Jedi Ace (and Jedi Weapon Master) levels, but as of the assault on the temple, how could he have the prereqs for Sith Lord? Unless they are changing that too, it requires 8 ranks in Knowledge (Sith Lore), Read/Write Sith, Speak Sith and a total of 8 Ranks in Dark Side force skills. Would Anakin just happened to have that when he went to confront the Chancellor? I also don't like the idea of Anakin gaining 6 or 7 levels during the Clone Wars (the version of him in the RotS Minis book is Fringer 1/JG 11, this is F 1/JG 5/Jedi Ace 2/Jedi Weapon Master 3/Sith Lord 2), and his Episode II version was Fringer 1, JG 5. Movie characters gain levels pretty slowly in Star Wars, and by all the other EU materials Anakin was only knighted as a Jedi about 6 months prior to Episode III, although it has been suggested that maybe the council withheld his Knighthood longer than it should have been (in other words, they didn't confer it at Level 7), giving Anakin real reason to be upset. The only other character who gains levels at a rate of about 2/year was Luke (who went from Fringer 2 to Fringer 2/Jedi Guardian 7 during the 3 & 1/2 years of the original trilogy).