Doesn’t Brandon limit himself to 1 revival per series? We already have Szeth. Reviving another character would violate that rule.
Form a in-world perspective, how could reviving him be achieved? Odium could turn him into a Fused-like being, he could be a cognitive shadow, or something unknown. All of these possible methods point towards Odium as the culprit, as Cultivation seems to play in the background. Why would Odium revive a possible Bondsmith? This Gavilar we are seeing, he probably wouldn’t want to serve anyone, not even a Shard. Odium has also been preparing Dalinar for a long time. Killing Dalinar’s brother would be another pain Dalinar could give up. Finally, it seems like Ulim was the one who ordered the Listeners to buy Szeth. Ulim serves Odium, and why kill him and revive him? Why not just fake his death?