TC-
You forgot total rewiring :D
You're absolutely right in 99% of the cases in Detroit, too. You don't get something for (almost) nothing, which I learned when I first decided I wanted to start investing and chose Detroit as my petri dish. I spent about $1,000 on property inspections for prospective purchases, to see what I would be getting into (considered it the price of doing business from thousands of miles away). The inspections turned up exactly what you're talking about- rotten roofs, AWOL plumbing, AWOL bathroom fixtures detached garages about to fall in on themselves, basements taking in water, outdated/missing furnaces/water heaters, nightmare rat's nests of outdated electrical wiring.... The list goes on and on. I'm glad I spent the money.
As for neighborhoods, that's much harder for me to judge from a distance, since I'm originally from Texas, not Michigan. I have to rely on what other people tell me/what research tells me.
Oddly enough, all this hasn't put me off Detroit. I've enjoyed the learning process immensly (which makes my wife doubt my sanity even more than she did before), and it made me keen to find that one REO house that, while not perfect, is not a money pit about to collapse. Which I think I've done. More importantly, at some point you have to stop dreaming and scheming and start doing.
The bank has accepted the offer of $7,500 on the house I chose. Roof is new, wiring is new (new = less than 5yrs in my book) interior of the house is in good condition if dated, detached garage will not fall in on a car parked inside, basement is not an indoor pool when it rains. Yes, it'll need a new furnace and hot water heater, some plumbing, and the like, but even taking a dim view of neighborhood comps, purchase price plus repairs minus sale price should see me net $30k. Which to me is worth sifting a lot of sand to find a gem.
And if this all works roughly acording to plan, then I'll be able to take that money and start sifting sand in the $10,000 to $20,000 range...