What if Sion's passive revived him if he lived for a long enough duration?
As in, if he's allowed to wail on something for long enough (or has an absolutely absurd amount of HP)
Sion usually dies in about 7-8 seconds if left to himself in passive. So if he can live for say, 10 seconds, he'd revive with 30% of his HP
Not a change I think should necessarily happen over a different buff for Sion, but I always thought his passive was worth exploring further
EDIT: LOL