Like Itachi said, every Jutsu has a weakness.. So why should the Death Reaper Seal have none?
Also we don't know what Orochimaru discoverd in his laboratory, it seems like he had a lot of time researching various things, coming up with some more or less "great" Jutsus. Maybe Orochimaru feared to be sealed / to have to seal himself with the Death Reaper Seal one day (for whatever reason), so he searched a way to escape from it if it would've happened. He was somewhat of a genius, so it is possible.
I think it's not that unlikely to happen that we may see some Minato or Hashirama beating the crap out of Madara.
If he can be f***ing revived in his prime, why shouldn't the good guys also become a chance of coming back?