Right now, it seems all of the successor projects are working on lore and designs. And while it is good to see where you can go, I get a little afraid when I see how complicated the lore is becoming.
We are, for better or worse, "spoiled." Our lore and factions were so well done and compelling, our first tendency is to try to duplicate it all in a successor. Well have our "faux Arachnos," our "Rikti clones," our "time travelers," our "paranormal scholars," and we'll place them in our games to make them familiar to us. But the danger is, as always, can it be done well? And, also, where would you be able to grow?
I would urge the successors to think of this opportunity as a chance to apply the lessons of CoH, but not in terms of duplicating its "mature" state. Instead, try to imagine back when CoH started, and recall how simple the lore was at launch.
CoH, when it started, didn't have a very complicated lore. It had your basic gang wars (Hellions, Trolls, Skulls), the clockwork and the Rikti, but that was about it. But what they did, they did well, and they kept a lot of the lore open ended enough to where they could fill it in later.
And fill it in later they did! Every issue seemed to delve deeper into the existing lore, and added to it. Soon we had Shivans, Freakshow, Arachnos, the Midnighters, Carnies, Orobouros, the Shadow Shard, the Praetorians, and so on.
But it didn't start that way. It started simple, and grew from there. And the lesson we can draw from this in terms of game design is that you have a much better chance of creating a compelling environment when you start with simple factions, but execute well.
When you start simple, you can always make things more complex. But when you are complicated, with dozens of factions and enemies, all vying for your attention, everyone loses focus. The developers lose focus, the players lose focus, and the concepts lose focus.
Now for my part, I would have no problem diving into a game that had...say...two or three factions of "bad guys" we had to take down, if those "bad guy groups" were really well done. And "really well done," for me, includes lots of minions, lieutenants, bosses, signature characters, story arcs and background info.
I would much rather have that than...say...the five or six meta-narratives that were going on simultaneously in CoH towards the end. That's something you can build toward, but initially, it would be confusing to me.
Don't make the city "too interesting," at least at the start. Give it a chance to breathe.