Let's discuss the next set of villains for the third game (spoilers obviously).

I'd really like to see the No Man's Land angle come up for the next game. They've got a lot of similarities to it already, and they've got the groundwork to bring it out in an impressive way.

The earthquakes of No Man's Land could be easily assigned as the seismic activity caused when the League of Assassins excavated the Lazarus Pit (the reason Amusement Mile is mostly underwater), and regardless of Batman's efforts in Arkham City a lot of stuff has gone wrong, what with Tyger no longer functioning and the Police Force weaker than ever thanks to Sharp's meddling. What convicts remain, and we know there are enough of them, are ready to spill into the streets even without Scarecrow being poised and ready to set off who knows what kind of hellish fear bombardment.

Azrael is already telling Batman that Gotham's rapidly heading towards ruin, and that it will be a catastrophe that comes in the wake of what happens in Arkham City that causes the final collapse. There are heavy duty weapons everywhere in that city thanks to Strange's shipments to the Joker, and the power balance has completely collapsed with Joker dead and Penguin trapped by Two-Face. Catwoman deals to Dent, but he's still the strongest force in Arkham following Bats' dealings with the other two villains.

I really want to see them play some more with the gang warfare dynamics, and I think having a storyline that isn't strictly linear could really help that. Something like a point in the storyline where Bats needs to do three different things, but the game gives you the choice of which to tackle first: going and saving someone who isn't in immediate danger but is trapped within one of the foe's (for argument's sake let's say Two-Face) strongholds, going to beat information out of the Penguin who's been teasing you with knowledge of one of the major ploys going on, or investigating an aggressive gang whose leader is not yet known, but who has been taking territory quickly.

Player one might want to know what's going on, and so they go after Penguin and because of this Cobblepot's territory shrinks back, allowing a few other gangs to take a slice of the pie, notably the aggressive new gang gets a bigger chunk. Your friend in enemy territory sneaks in a bit deeper, and as such is a little harder to get to, and the new gang territory is larger, meaning you have to search further for their leader. Player one, hungry for more answers, goes for the gang leader and eventually uncovers them, learning more of the plot, and then gets a transmission saying their ally has been found and needs help - now. The third and final slice is now a timed mission, because it's been left long enough for that character to be found. As a result, after all three objectives are complete the game moves on to the next step in the story, but the gang territory in the layout remains as Player one's actions have altered them: Penguin's territory is smaller now, while the new gang has an impressive chunk of land and the remaining gangs are mostly unchanged beyond spreading slightly into Penguin's old territory.

Player two might go straight for the gang, stopping their expansion early, before saving their ally and as a result their final objective in going after the Penguin is considerably harder, with the end result being Penguin has the biggest amount of territory, and the new gang has quite a bit less.

And so on. It'd add so much to replay value to be able to watch the war for the city evolve based on Batman's priority list, and the missions would range in intensity based on the order you complete them in.
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http://www.gamefaqs.com/boards/959557-fallout-new-vegas/60421043
You don't have to be a fan of Fallout, just a fan of a decent read.