Skoll Shorties

I don't know what precedent you're using to argue this since they've been setting up Saurfang to take her down from the beginning, and now are also giving Baine motivation to do so as well.

Who cares about Benedictus dying? He was never a big character at any point. A completely undeveloped leader that then is corrupted and dies.

You could make the argument then that Khadgar kills everybody because he was present for a few major character deaths. Benedictus was a nobody, not connected to Thrall's story, and his role in Benedictus' death was never even codified into the story afterward.

You're just basing this then off of who gets credit over killing somebody. In the story of Cata it made sense for Thrall to wield the Dragon Soul and kill Deathwing. Thrall's whole story in Warlords of Draenor was to put down Garrosh for good and he did just that.