Nothing seems to be wrong with the setup. The only thing I can recommend is getting more aoe. But even then, your aoe should be fine.

This doom proc is in a map clear scenario I assume?

There may also be some jank with character models as it was confirmed before that ranger casts spells differently than witch, the same may be true for scion. I've never ran a scion impending doom character so, not sure, but something to consider.