These are some very interesting ideas. Especially what you suggested Tancred, with cities becoming overgrown and monsters moving in and taking up residence all the way up to a champ. That would be crazy exciting.
Beyond that, before anyone starts talking about NPC towns I'd like to just point out that we've spent the better part of a year putting the emphasis on player run towns by awarding "banners" and now offering additional opportunities to achieve improvements to those towns.
Remember your EMs are people too and we have to do pesky things like work, eat, sleep, and tend to your families. We already have the schedule about as packed as it can get.
That being said, what would definitely work is if townships wanted to sponsor various events in NPC cities and wanted to request small enhancements...such as tables for a bizzare. Or whatever the case may be.
Also remember that as we develop RPCs and progress the story, NPC towns are what we use, because they are there and because they offer a fairly empty palate to give the event some decorative enhancement without taking up all of our precious hours building something from scratch.
Also, and this is a big one...remember what we have on the horizon. You already know how much I like the ocean...you can count on full immersion here on Chessy.