I played a rebel list in the EC with Jedi Luke and ERangers and finished swiss as second place only losing to the new champion. In the top 8 I lost due to some mistakes, risky playstyle and not thinking ahead enough.

But in my opinion rebels can compete just fine. Luke needs a lot of finesse to play being a brawler. You really want to get those attacks out and putting him in the wrong spot first round can deny that second attack in the next. He is also more swingy with his white defense die and an gby attack without rerolls, at some time there will be those dreaded three surges... and having his command card often means another dead weequay.

The rangers might be bad for the middle part in jabbas palace, but you don't really need to be there. Just control the great hall and rancor pit because there are the most objectives. If my opponent doesn't want to open his door and completely ignore the objectives he will feel the point difference at the end of the game if my smugglers score 4 to 8 points a round.