Team Help

YungMoney

So I've been playing a while but haven't really looked into who's good and who isn't. I'm looking for some advice and help. Right now I'm lvl 57 and my best toons are Sid (4*), Luke (5*), Boba Fett (4*), Lando (4*).. I have low levels of Poe (3*), Phasma (3*), Savage Oppress (4*), Dooku (3*)..

I honestly need help because my teams are getting slaughtered in GW and are not doing well in arena (currently ranked top 250 or so but getting beat by people with lower power.

I'd love some advice or any theory about who is good and who I should focus on.

Thank you so much!