[ZeoRangerV]

Having simply a start point and an end point isn't exactly a story though is it? There is absolutely nothing of substance in gen 2 Kanto-wise other than Team Rocket's resurgence (and even that now is pretty minuscule in the grand scheme of Pokemon games). So many new things have been introduced since gen 2's story that there's plenty that can be done to keep a sequel interesting.

Just because you know something happens doesn't necessarily make it predictable. Just from "active volcano" you could get a storyline with Team Rocket (or whoever, who said it has to strictly be Team Rocket) again trying to capture Moltres from it and have some sort of Mega/Primal Moltres wreck the whole thing. And that was something I came up with in the time it took to write this post.