I'm still with the others. I really liked Loken and assumed he would be the series main protagonist in a sense, that somehow he and others would survive Istvaan. So when he 'died' I was like, well fuck. And it really hits home just how brutal that betrayal was, that even Loken, loyal to the core, with all the beliefs and traits you want in an astartes, still dies, killed by one of his closest brothers. No one is safe, the betrayal is absolute.
And like others have said. Him surviving, just seems meh. I now read GiF, and whilst Torgaddons death still sucks, I see Loken get beaten and just sigh, as he somehow survives. It just completely took the tragedy away. We had Garro, Qruze, Keeler and the others survive the massacre. We didn't need any survivors on the surface. I don't buy into the whole 'Loken died on Istvaan, he's completely different now' because reading Vengeful Spirit, he's still very much Loken.
So yeah. He should have died. Him surviving quite literally ruined Istvaan III for me.