@Darren Liedtke, Hey neighbor!
Great question, at least it's the one I'm always thinking about as I drive through the city!
Broad question, so I'm just going to answer it in kind.
I was in Boston recently, and while taking some mental notes about how radically different the real estate market is (the value is all in the land, and speculation about the value of that land), I did unintentionally realize how backwards and uncomfortable Milwaukee is in ways, namely, it is so profoundly segregated. It's not only a cultural and civic problem, but it also poses radical uncertainty for the investor if they're trying to make an appreciation play (which, all cards on the table, I don't think you really go for in Milwaukee - by chance, maybe, or they cash flow and you get lucky, but they have to cash flow). You don't just have to rehab real estate, you have to change perceptions of an area, and not just socio-economic perceptions, but the racial ones too, because, sad and as unfortunate as it may be, in Milwaukee race is identified with crime and 'sketchiness,' and property values reflect this in a very strong way.
I was also just reading a real estate book by Brian Murray (he was on two of the podcasts, don't remember which), where he talks about 'buying on the line.' The line is arbitrary. Case in point, as your hack appraiser made clear, the line is arbitrary but definitely real. A duplex on Holton at 35-40k is maybe worth buying, but a duplex literally one block over on Booth is a steal at 100k. Why? It's the same god damn house.
For what it's worth, I still think River West is legit. I bought a four family on Fratney and Chambers that I'm happy with the cash flow and equity play on, and will close on another 3 family on Weil and... (Nessun Dorma) in about 30 days. Same goes for that one. I'm not sure our neighborhood's all done improving yet. You can buy B/B- property and get B/B- tenants at numbers that will still cash flow well and you have as good a shot as any at appreciation.
I talked to a lady that owns a commercial building on Holton and Center over there (you'd know the one), and it's just sitting there, lame and vacant, not doing anything. How many of those would it take to change a corner and the way people see it? To get people coming around or even a happening little restaurant. Not sure. We're fighting the problems outlined above.
With respect to more general lines, hard to say. Sometimes I think the revitalization will follow the housing stock. Brewer's Hill being rehabbed, for example, makes sense because of what they had to work with. Good bones, nice victorian houses. St. Francis or Cudahy, for example, are a lot of little match box, pre-fab things that I can't see people really wanting to revitalize. (I think this is actually the problem with respect to Buffum and Richards and the other couples dumps: no one cares about the houses, because they suck. Maybe Gorman & Co. could just buy the whole strip Keefe to North and rehab all of them on tax credits or something...).
Anyways, I'm trailing... Let's get coffee next week, neighbor.
Best,
JTM