Part of the Daelin issue for BfA is that we experience him, quite often, through the lens of the Kul’tirans, or through the experiences, memory and regrets of his daughter.
In the case of the former, it is entirely logical, but not accurate. To the Kul’tirans, their king set off to save his daughter, who escape the Scourge to Kalimdor. In their minds, Daelin gets killed by barbaric monsters from the second war because Jaina didn’t support him. Eventually the reality of the new horde would become apparent, but the narrative would be heavily entrenched. Daelin was a noble, fallen hero.
Jaina knows the full truth of what happened and why, but she’s been jerked around so much by this point she’s taking the actions of a guy who, at the time of her father’s death, was moping around Nagrand, as evidence that her father’s actions were just. It probably doesn’t help that she walks full faced into a national level guilt trip.
Though I’ve only played through it once, so my memory may be faulty, when we rescue Jaina and she’s coming to peace with her grief, she remembers the choices her father made, and chances to change direction he ignored, and the consequences that resulted from his own choices far more than her own.
So Daelin isn’t redeemed, except in the eyes of the viewers who probably were in the “did nuffin’ wrong” camp to begin with and want to see that. He IS walked back from an (intentionally for the narrative) idealized image to the reality, even recognized by Kathrine. Naturally, as this is all Alliance exclusive content, it isn’t really critical for it to show what the horde feels.
In terms of the Horde’s motivations, would it have been nice to give a nod to the pre-cata occupation of Tirigarde keep by Kul’tiran forces? Yup. Would it have been useful for (given both factions were really after boats initially) proponents of the war to remind the Horde that Daelin tried to destroy the Horde in its infancy, and that Kul’tiras still has statues of the guy? Yup.
On the other hand, in both cases, they made Zandalar about Zandalar, and Kul’tiras about Kul’tiras. We got to focus on the internal aspects of our new buddies, rather than finding a reason why they hate that other island. So, there’s that.