I find myself in the third position on this, in that I wholly believe the Exarch's heroic sacrifice against Elidibus should have been his actual demise. It would have been a fine enough sendoff to his character, and we could still have woken up the sleeping G'raha Tia at the Exarch's behest. Then G'raha Tia could have joined the Scions, perhaps fashioning the Exarch's half-filled soul crystal into a job stone, and the story going forward could have dealt with him trying to live up to the legacy his future self left for him instead of... awkwardly fanboying out over characters like Lyse, Matoya, and Estinien.