2 possibilities if Young Jean is more efficacious to try than old Jean...
1. Gladiator is trying to change the past.
2. Gladiator is trying to keep the past the same as it used to be.
Old Scott died when Young Scott died, therefore killing Jean will resurrect D'Bari, even though it will frack up ten thousand other things.
Just finished Thunderbolts.
The Leader to Mephisto: "Sure you may, MAY be more evil than me, but I'm smarter."