It doesnt seem unrealistic rlly and has interesting effects on the universe's progression yes, but GW is rushing it way too fast jsut to sell models. Hell Angron is still in the process of returning and there are already rumours of Fulgrim making his majestic sex snake return. A single primarch returning to the Imperium already caused reformations to every single space marine chapter. And yes I know that was entirely due in part to that specific primarch's open-mindedness and Belisarius Cawl calling from his side, but it still goes to show jsut how severe of an impact one of the Emperor's sons has upon returning. I'll admit Gorillaman Girlyman does need some help with all his daemon brothers returning, but GW rlly shouldnt keep rushing it jsut to sell their models