I think we are really leaving untapped the potential that the sea of Nurnen offers as a location.
There is the Kraken, which routinely attacks the Fishery (location available in Shadow of Mordor), just because it gets angry. What makes him angry? Likely the orcs disrespecting the sea, overfishing, razing the seabed and throwing corpses and trash in the waves.
But also. Pirates! I bet there are lots of pirates sailing the sea of Nurnen. They do everything that an orc loves: raiding, fighting, drinking, and they obey only their leader, not Sauron or anybody else.
Maybe there are other creatures, like sea Maiar or spirits... Maybe sirens!











