In 2012, TPS already refused to sign the release and only after meeting with MW, they agreed to sign. So that tells me that there are something. If it is next to nothing then what do they have to lose by not signing? They already refused to sign.
Then the LT spent a total of 91M since 2012 to do something. If our return is close to zero then they should wrap it up quickly and give us back at least 80M
Then there is the Safe Harbor and securitized assets. There are signs that there are some SH assets that the FDIC could not seize and they don't like it and tighten the rules in 2009 to restrict what kind of assets can be put in SH. So either WAMU put a good portion of assets in SH or do nothing but it makes no sense to spend the effort and put a little bit.
And then experts like HM and Justice found some balance sheet data that show that the FDIC retained as much as 40B.
Taking into account all of the above, I cannot say that the return is close to zero. At the same time, I cannot be sure that it is more than 20B either let alone hundred of billion.