I have to be honest, I can barely bring myself to do the Ground War Assault Battle. It just takes SO LONG at each tier because we can only use low-damage teams. I understand why Resistance was removed...
Fact still remains that it takes too long. And I just put my Bastila team on auto and did not even make it to GG in mythic tier. Seen all kind of BS from giving Rally buff to Ahsoka Tano and Old Ben to characters attacking random targets without focusing fire. BTW they all are 7* and G12 with pretty good mods. Also there is no reason not to have option to sim lower tiers.