A useful thing to remember here is the seller side of this transaction - the performance measures for Fannie Mae employees responsible for the sale of these properties are based in sales execution and time as compared to several independent sources of value. And not for nothing, as a taxpayer you should appreciate that -- they've sold nearly a million foreclosed properties in the past 7 years and using this methodology, lost far less money as a consequence.
Given that, it's completely unreasonable to expect that they're going to accept (or, honestly, even consider) an offer significantly below list price. This isn't unusual -- you wouldn't typically take a lowball offer on your house, why should they?
What you will see is that over time list prices will drop if the property hasn't had an acceptable offer during fairly regular 30-day or 45 day increments. There are deals to be had, for sure, but if what you're looking for is a significantly mis-valued property, they can be hard to come by.