I proposed the 6v6 with 2 leadership bonuses as a fun variant for TW. I think the Devs want to keep GA a bit more serious.
I like the idea, there's are so many BH & Rebel leadership abilities to mix and match but here are a few of my favorite ideas.
IG88 + Vader (need moar DOTS!~)
Chirpa + Teebo (Choo Choo here comes the TM Train!)
Talzin + Asanjj (the quick & the dead)
JTR + Fin (Expose the TM Train)
CLS + Akbar (Assist and counter)
Krenic + Veers (Watch out for the Deathtrooper)
Cody + GK (Clones and the General)
Old Ben + Luminaria (Get out of Dodge)