The problem with them is that they rely on TONS of assists and quite literally every non-unique buff in the game to do pretty much anything. If the opponent has B2 then you already lost. Sure they do good damage when they have Crit Damage Up and Offense up, but without that they are terrible. And without HoTs and assists they can't sustain themselves either. They can work occasionally, but against CLS and Rex lead they are the worst possible team you could think of to use since they will counter attack you to death within 2 turns, literally, and you'll just feed Rex lead an insane amount of turn meter (you can daze them with Logray but they'll almost always have R2 on the team so it won't matter after 1 turn anyway). My advice to you is to not waste resources on ewoks. Just go for rebels, the devs love giving them new OP characters all the time and it won't stop, so if you farm rebels you'll always be at the top. Or find a way to counter the meta, its a lot harder but its also a lot more fun than using rebels. For example, I still use my droid team in arena on an old shard and with BB-8 I'm back in the top 10 :) I don't win every fight (probably 7 to 9 out of 10), but If the enemy team doesn't have Raid Han, or 2 team cleansers, I have a really good chance of winning.