Interesting post, mtcoco!
After learning the hard way, I am a big believer in "LOCATION LOCATION LOCATION" as the 3 most important factors in real estate.
On the face of it, this sounds like red flags shouting "STAY AWAY!" But, as you say, there are nice homes there, and more on the way.
I, personally, am leery of properties like this. Remember the Love Canal (I think near Buffalo, NY?) Wow. Poisoned water supplies, etc. Nasty situation, probably to this day.
There might also be issues with settling. But then again, you hear of old landfills converted to golf courses, etc. So there's that aspect...maybe the "Location" isn't so terrible...
The thing that's potentially most appealing about what you mention (again, to ME) is not the new developments--which they just seem to stick up everywhere these days--but the fact that 80 year old homes are there, and are presumably well maintained and desireable. I'd think this history goes in this area's favor--especially if it's been desireable all along. I mean, if an area's been desireable for the past 80 years, the chances are that it'll continue to be so.
So, this may not be a scientific answer to your question, but I always seem to go back to those 3 little words....Location, Location, Location!
-k2 in CO.