I always imagined a sequel would be like how the Nier games do it. DE2 would be best if it took places decades before or after the events of the first game, also in a different part of the world. I really do love it when sequels aren't just straight story extensions. I love when they become something else with the setting and focus on expansion of the core elements.
I'd love it if the entire events of first game were just a footnote of a footnote of a larger history. Maybe you get one passing line about Revachol and its reputation for strike breaking and that's all. Everything you and Kim did felt massive while you were in it, but how do those events seem 120 years later and on another continent? That's what I get into.