That's a possibility. He's only called the "death titan" in the files (and one of his moves was renamed from "Grasp of the Death Titan" to "Grasp of the Unmaker" from the PTR to live), meaning that that may not be his actual role among all the other Titans. Though, he absolutely uses death-related abilities, which the visuals were reused for Bwonsamdi, Gorak Tul, Drust, and Necromancers in BfA. So, not out of the question.
There's another theory as well, which is that he wasn't fully "formed" yet when we encounter his world-soul in the Seat of the Pantheon. Which would also make sense. There's no official word on why he looks the way he does. Alex Afrasiabi called Argus and Outland both "death titans" at Blizzcon 2017, but Outland isn't a Titan at all, so that's iffy information as well.
For transparency, I always figured the damage to Argus' world-soul was from the damage to the planet. It's just speculation on my part, since it matches well. But other theories involving his abilities and formation are also valid at the moment.