One big set from each episode would be awesome. For example, the arena in episode II, including all three beasts. They probably won't be able to cram in all the characters involved in the fight afterward, which brings me to my next idea.
Moar battlepacks. Here's some ideas.
battle droids (with 1-2 hover things and destroyer droids); Gungans (with 1-2 ostricamels, would be nice to bring them back as a whole); royal guard (the guys in the brown uniforms, don't know what special units to include)
battle droids (the darker-coloured ones they had, with super battle droids); Genosians (would be cool); Jedi battlepack
(this would be awesome, all the Jedi involved in the huge arena battle. this is good not only for said battle, but overall fucking awesome)
Wookies (oh hell yes. including Chewbacca, and a small vehicle that I think
exists. didn't they have some sort of copter or something?
stormtroopers; death star crew (grey-suited guys, including 1-2 of those gunners with the funky helmets, as well as a mouse droid)
Ewoks (also fuck yes. includes glider and maybe a mini catapult?); scout troopers (1-2 speeder bikes, I would like a few of these guys)
snowtroopers (I know they already have one with snowtroopers, but this one should include more actual figs and less random stuff. also don't know what to add)
Also, original trilogy packs with the main characters from each side. Good side would have Luke, Han, Leia, Obi-wan, Chewy, R2 and C3PO. Dark side would have Darth Vader, the emperor, one of those red guards, the commander of the death star, Jango Fett, and Jabba.