The Meta is that Rebs are better right now. Look at the TTS league, all the top squads are Rebs. The only reason that the Empire is represented in the top 5 in UK tourney is that most peeps are plying Empire right now. So a rebs winning the tourney even proves more so that there is an unbalance in the force till Vader gets help or Fett is the real deal.
Also, my son and I have been battling 2x per week over the last 3 weeks. He plays Empire I have rebs. He is is better than me in all of the other mini games that we have played over the years, and even being top in the US and Canada in the old WOTC Star Wars minis game which has a higher degree of skill and tactics than Legion (this is not a knock on Legion, it will get there in time). I have been beating him on a consistent basis, some games we dont even get to round 4 cause there is no chance of him winning. He has tried a few different archtypes- conclusion, Vader and ATST is well overcosted. Luke and Leia together are much better than Vader and cost only 30 pts more.
But this game is still loads of fun.