not likely... the walking NPCs were timed to the server... because they had to be able to randomly say things about randomized user accounts "did you hear they're making an action figure of X?", or spout off the time or date or usage stats when clicked, or whine about their purse getting ganked, etc.
Ya know though... the walk-path information IS available on the client side. Anything non-critical tasks you can push out to the client means that much less load on the server, obviously.
From a design perspective, I wonder sometimes if the industry does not reserve too much for the servers. Some things obviously HAVE to involve the server as the authoritative source, to avoid cheating if nothing else. In this case, the one strong argument I can make for the wandering NPCs being tracked by the server is so all players would see them in the same spot. But there might be other ways to handle that.
Just off the top of my head, you could run the NPCs around their walk paths based on time. Sync Paragon Chat with an NTP time server probably on login and every time you zone, and everyone's clients would probably stay "close enough". If you really wanted to go nuts you could keep them closer than that, but why bother? So long as you keep them synced within a few feet on different player's clients, the only people who would ever realize they are not standing in the exact same spot are dual-boxers - and THEY would be very likely to be time-synced within milliseconds of each other anyway since they're on the same lan segment and uplink.
You'd only need to "track" NPCs in the zone / room you're currently standing in, which probably helps. The original server had to keep them moving in ALL zones, your client really does not care about NPCs in a zone you are currently not in. The other functions of NPCs maybe could be faked, too. Time is easy, as is anything referring to YOUR character.
The NPCs who mention other people's character can probably even be handled, since Paragon Chat "knows" who else is currently logged in. That gives you a list to work from, add in your global friends, and now you've got a probably much smaller list of possible heroes for them to comment about. Might get a bit weird since villains and heroes are mixed willy-nilly, but even that could be finessed if it's possible to query the info from the other Paragon Chat client when it is needed.
The network environment is VASTLY different than it was when CoH was first designed. And for that matter, I suspect based on what I see from the outside looking in that a lot of things are done a certain way in the industry cuz that's how they've always been done. A project like this gives you the chance to discard the old ways of doing things if it makes sense.