I do not like the deck building mechanic at all. I like the complete creative freedom that comes from the ability to choose ALL the cards I want for a deck to focus how the deck plays. The idea of choosing some and then getting stuck with the rest is not my idea of a good way to build a deck. Calling it a challenge does not make it a good mechanic. I would prefer to have a mechanic like Net Runner where if say you were playing Jedi you could take X points of cards from the other two sub-factions and have complete creative freedom of how I make my 50 card deck and what objectives I use.
I'm not a fan of having starships and characters fighting against each other in the same battle either. The idea of my Vader or Obi Wan being killed by a X-Wing or Tie fighter in combat just doesn't sit well with me from a flavor perspective. I really, really want it to be a great game but I fear it is flawed through these mechanics.
I only have limited exposure to this game through the Demos at Gen Con so maybe I am completely wrong and I will be calling you brilliant after it releases but I think not.