Now that the first half of the game is done or nearly so I'm pondering the next part

The player has been robbed of the staff and reported to Minas Tirith.
They say that orcs sightings are rare and do not recognize the symbol of their shields.
Orcs were last seen in the Moria so the player is sent there to investigate.
He descends into the mines, defeats many vile orcs before arriving at their leader (who works for the Istari)
who has an open portal to the Empty Lands. Upon defeating the leader (who does not die but is set at 1 HP)
he interrogates him about the staff and thus knows more about the story and enters the portal.
The portal is one-way and the player is stranded on the Empty Lands, with no allies or ressources to speak off, lost in an hostile territory full of orcs and easterlings.
The Empty Lands are not part of middle-earth for beyond the sea of Rhun lies the Eastern Sea and beyond it yet the Empty lands, it is an other continent.
The main feature of it is the Walls of the Sun with the Gates of Morning, through which the Sun arose, before sundering which made Arda a sphere.
Scattered trhough the lands are bastions of orcs, settlements of easterlings, damp caves full of trolls and undeads, even a desert where many of the last dragons of Arda live.
But all is not without hope, a group of Avari (elves who did not follow the valar) and humans have settled near the Walls of the Sun a long time ago and now resist to the power of the Istari, but they fight a losing battle, overwhelmed by the numbers and soon they will be gone. (An occasion to open new classes ? Sun priest ? Light warrior ? )
The wilderness map will be undiscovered at first and must be explored (random/part random map ?), the player will learn that in order to bring down the Istari their power must be weakened by breaking the ties to some of their allies.
I imagine a few dungeons that must be explored and their boss killed into order to destroy a "binding orb".
Binding orbs bind the life force of their alleis to the Istari rendering them exponientialy more powerful.
This could act as a difficulty setting to, the more orbs are destroyed before taking on the Istari, the "easier" they are.
Thoughts ?