There is a reason that cannot be done.
DOS sets the date. Lets say hypothetically they make dates current as per your suggestion and let everyone get the EAD.
USCIS would then have a candidate set of applications all the way until 2013 that are eligible to get GC. USCIS issues GC to all applicants that are current. Hence FIFO wont be followed. It might be a bigger misery for many (2007/2008) who will have to complete against everyone to get their GC.