When I first started playing, Westside had just been remodeled (including the addition of Westside High High School). Now it's had another reworking.

But what about the other parts of Millennium City?

Here's what I'd like to see in a City Center redux:

1. Houses of Worship. I'm not aware of any of these in Millennium City as it now stands.* In City Center I think there should be at least a Catholic cathedral, a couple of Protestant "megachurches" (large structures), a mosque, a synagogue, and a Baha'i temple, all easily recognizable as such and given distinctive names. To keep from taking up too much map space, these (or at least some of them) can be put on the edge of the map, judging into the active space just enough that a new Mission can send the heroes to those locations. There can also be a few smaller churches here and there, both as separate buildings and of the "storefront" variety.
   
2. Police and Fire. Basically, the same as was recently done in Westside. And along the same lines, MCPD HQ is actually in Downtown (there's a building marked as such, IIRC, right near the UNTIL building); I think I'd change the name of the place with the Nemesis contacts "The MCPD Data Center."
   
3. Less Obvious Criminal Activity. PSI likes to disguise itself, but the City Center has VIPER and ARGENT agents right out in the open, sometimes in the process of committing crimes right on the sidewalk of a major thoroughfare. PSI wanders about in the shadows or in disguise; let's put as much of VIPER into alleys as possible, and limit ARGENT's obvious activities to legitimate-looking security patrols. "Detained" citizens can be in out-of-the way places, and ARGENT should not automatically go aggro just because a superhero walks by. And for heaven's sake move those guys just outside the Inventions Shop -- ideally, make "The Glasses Menagerie" (the Mission they're around for) an Instanced Mission.
   
4. The Millennium City Eight. Digital Hero #13 detailed eight superheroes who were part of this loose confederation of heroes protecting Millennium City (they are also featured on the cover of the 5th Ed version of Champions Universe). I'd like to see them featured in-game; perhaps two or three could be added here as Contacts for a new Mission arc or two.

*To be fair, I've hardly been in Westside since the most recent remodel. I don't know what the new police and fire stations there look like, I haven't yet encountered Little Italy, and I don't know if there are now any churches there either. I think there already was a Westside Mission, but that plus a few storefront churches, a small Catholic church or two, and a Buudhist temple in Chinatown would be appropriate the next time there's a pass.

Griefers - These people will grief anything. They're here for that purpose, not to have fun in the game. Putting churches in the city will not change that one way or the other; they'll find something
to give people grief about. (Frankly, I'm just a tiny surprised we haven't had a bunch of heroes form an "Occupy Millennium City" Supergroup to converge around the various City Center banks and other institutions.)
Mainstream - I've seen this worried about in many other contexts, but I've never seen it actually happen. In addition, anything not included in the playable areas can be explained as being in another part of town; Northside would probably be heavily dotted with small churches. And in real life many smaller churches meet in school buildings, community halls, and living rooms. (Though to be fair, I did forget about including an LDS stake and a Kingdom Hall; these should at least have some visible representation.) I'm not looking for representation here; I'm looking for better believability, and a city the size of Millennium City having no religious institutions at all (except the Cult of the Red Banner) just doesn't jibe with social reality.
Cults - I don't even understand what you mean by this, let alone what it can possibly have to do with what I suggested here.
Devs - That's kind of their decision, isn't it? They've redone Westside twice. If they're going to stop doing art rewords and focus on other matters in the game, then fine; I'm all for it. If not, I'd rather they did something in another area than Westside, and City Center seems like a logical place.

Yes, I know about that. Didn't I mention that in my OP? The MCPD Headquarters that I suggested should be renamed the MCPD Data Center, in favor of the larger MCPD building Downtown?

I wouldn't be opposed to this either. I can see where there are some geographical gaps to fill in the Southwest Desert, expansions to certain aspects of the Canadian Wildnerness, and so forth. For purposes of this thread, though, I'm just talking about City Center here.