The Red War affected Zavala more than anyone else, and his character development is interesting in that it is almost all negative. He is going down a hole of self-doubt and it is evident in everything he's done during the entirety of Destiny 2. Prior to the Red War, Zavala was a Commander who had never REALLY known a true, total defeat. As far as I can tell. I think The Moon thing with Crota was before Zavala becoming Commander. (correct me if I am wrong). After the defeat of Crota, Oryx, SIVA, etc., Zavala was riding high as an incredibly successful military leader. I daresay he was a bit arrogant in his belief that his Guardians could face and defeat any threat, no matter how big and scary. Then Ghaul came, and several things happened with Zavala specifically, that still haunt him to this day. 1)He didn't see Ghaul coming. He feels he should have. 2) He made a single decision that likely cost us everything. He chose not to protect The Traveler, opting instead to keep all The Guardians in The Tower until the absolute last civilian ship took off. "The Traveler can wait." He said. Those four words likely haunt his sleep every single night. Those four words cost us Our Light and The City. This, is the biggest tactical mistake he has ever made, and the consequences were incredibly dire. 3) We lost the Light and got our asses kicked. A complete, utter, humiliating defeat. Zavala had to personally sound the retreat, and he for the first time ever, completely FAILED to defend The City. He had to watch as The City burned and a foreign power occupied it and killed its remaining citizens, and powerless Guardians. 4)As if things couldn't get worse for him, He took the retreaters to Titan, where he ran into The Hive. Another mistake that cost lives, particularly those of lightless guardians. This has affected him for the worse. All of his actions since we retook the City, are the actions of a Commander who is desperately trying to NOT fail again. It has made him close-minded, insular, overly wary of any and everything that could possibly be a threat to The City(see: Rasputin), and unwilling to commit Guardians to venture too far away from The City for too long. He now has a tunnel-minded focus on protecting The City and The Traveler at all cost, to avoid failing to do so again, so much so that it has clouded his judgement in other matters(see Avenging Meme-6). He desperately wants to avoid a repeat of Ghaul. In short, he isn't a coward. Calling him a coward suggests that he is somehow afraid of Uldren and the Barons. He's not. He just can't see the forest for the trees, because of his guilt regarding his failures during The Red War. He's put on blinders where he can only see The City and its needs, because he failed The City once, and he's determined not to fail it again. His character arc is very interesting to me.