GAC feats centered on themes like the upcoming season 9 GAC feats centered on Troopers (Clone, Imperial, and First Order) are fairly interesting. I would like to suggest that themes like these would be more interesting if they were accompanied by some kind of special buff or ability for the affected units.
Simple examples would be additional health for tanks, offense for attackers, bonus turns for support, etc. More interesting examples would be Retribution+Stagger for tanks, attackers inflicting Tenacity down, and so on. Most interesting would be new special-event-type abilities that would allow the devs to use their imaginations and increase interest in pursuing feats.
Frankly, I thought we would be getting these types of "faction buffs" in GAC similar to the early Territory Wars with FO and Resistance. Do not recall seeing anything like this yet, though.