For that reason, I never get involved in those "policy decisions," but just stand by to check things. If it was just me, I'd just post everything that didn't have a copyright and deal with the annoying lawyer folks if they ever show up.
I do somewhat worry that we're setting back public domain use, though, with these sorts of decisions. It gives the continued impression that copyright works like trademark, in that if the company still exists, they MUST hold the copyright, by some magical definition, or if some magic number of publishers have used the property or "unimportant," then it's public domain.
Derived works, as discussed in another thread, can be very murky, but to me, the Library of Congress records should have pretty much the final say. In other words, people should have access to Marvel Comics #1 and New Adventure Comics #27, because the public does own the rights to those books, regardless of who "might" (but probably wouldn't, if they're professionals, since they have no standing to sue) send a Cease and Desist letter.
Again, though, that's just me.