In no particular order (the numbers are just so I don't go over):
1) A Fringe
Han Solo - A representation of the character for that surprisingly vast period of time both before he joined the Imperial Academy; and between when he was kicked out of the Imperial Academy for helping Chewbacca till when he got around to meeting Luke and Obi-Wan that Wizards apparently never once attempted to touch upon. Bonus points for giving him an attack and/or defense bonus specifically against Imperials (since he'd have a better idea on how they operate). For that matter, an Imperial Han Solo (for his days before he met Chewbacca) might be fun too.
2)
Kaleesh Generics to give Qymaen jai Sheelal someone to lead against the Huk.
3)
Chewbacca in Hijacked AT-ST - Complete with the 'Ewok' special ability. Or for that matter, just create a Fring AT-ST since they're always getting stolen in the videogames (amazing how often little bits like that cam get stretched out forever).
4) Some kind of
Jawa commander like a
Clan Chief or
Shaman (In the case of the Shaman, it could conceivably be a 'non-unique unique'.)
5) Likewise, some kind of
Geonosian commander, either as a generic or in the form of either
Poggle the Lesser or
Sun Fac.
6)
Warlord Zsinj, the man that Han Solo infamously told to kiss his Wookie, the primary antagonist of Arron Allstons X-Wing trilogy, and one of the more dangerous foes the New Republic went up against between Palpatine and Thrawn.
7)
Wraith Squadron uniques. Janson, Face, and so on. If you're feeling REALLY ambitious, maybe even Lt. Kettech as a new Wedge Alternate (Yub yub, commander)
8)
Shi'ido - the shape shifters first brought to light through Mammon Hoole who put Zam's Clawdites to shame (I imagine them allowing players to get a lot more use out of those savage characters)
9) An
ATT.
10) The
Ssi'ruuk. However, this would probably be best to save for a later set, since I imagine they'd need a new mini-faction of their own to truly be done right.