I would like to see two expansions, one with a generic Rebel Commander and the other one with a generic Empire Commander. In each expansion there should be enough cards and stuff to create your own specific type of commander for your troops with different abilities, skills and so on. You can give him a name and make your own scenarios and campaigns to play your own story in the SW universe.
For example, Dall Bango, a former mercenary from Nar Shaddaa, searched by the Empire, now commander of a special forces team of the Rebels, operating on Jakku ... etc. etc. ... you know what I mean.
In addition to the possiblities I talked about above, I have to say that I don't like to play with Darth Vader and Luke Skywalker as opposing commanders in a battle. For me, this makes no sense at all, because the two met each other on Bespin the first time and then on Endor the second (and last) time. There were no battles or skirmishes the two fought each other commanding troops during the original film trilogy. Of course You can say that all the SWL games you play with the two as commanders are "what if"-battles, but I'm no fan of this. It doesn't fit into the storyline between those two in the original film trilogy. So, if you don't want to use both in the same battle, you cannot play this game at all, because there are no other commanders to use. The same is true for Leia and General Veers (although an expansion like General Veers goes in the right direction).
So, I really hope and I would be happy to get generic commanders for the Rebels and the Empire.