This chapter is an odd one, starting with Bilbo waking up and then presenting the death of Thorin and then details on the end of the battle in backflashes, which somewhat distances the reader from them.
That the title of the chapter is “The Return Journey” also sets the reader to looking ahead to the journey back.
The eucatastrophe, to use Tolkien’s term, mostly occurs in the ending of the previous chapter with the coming of the Eagles who are a sixth army. This is supposed to be a surprise. But this is really not a
deus ex machina surprise as the Eagles have appeared previously and prominently in an incident which stresses their hostility to the goblins. The same is true of Beorn who now appears again.
The Eagles are more like real Eagles and not presented as servants of Manwë as they are in
The Lord of the Rings and even more so in
The Silmarillion.
Gandalf may be imagined to have a more decisive role in the fighting than shown. In
The Lord of the Rings, even after being brought back to life and full vigour, Gandalf alone is not the main figure in the siege of Minas Tirith. Gandalf is not the sort of wizard who can just say: “All foes vanish!” and have everything turn out all right. Gandalf could not heal Thorin either, so far as is shown.
As Tolkien writes in Chapter IV, “Over hill and under hill″:
Gandalf thought of most things: and though he could not do everything, he could do a great deal for friends in a tight corner.
Gandalf can help win battles, but no more so than some others. In a battle he is possibly equal to several Eagles and equal to Beorn at best. Gandalf might blast down a whole platoon of goblins, but how much would that take out of him?
One would of course like to know about Bilbo’s later hardships and adventures on the way home. Tolkien might well have written a sequel called “The Hobbit with Gandalf and Beorn: The Way Back” covering adventures on the way back in which Bilbo himself is not in great danger, as
The Hobbit says. Hugh Lofting did something like this with
Doctor Dolittle’s Post Office which in a short introduction in the book publication claims to be a return home from a later untold journey but which the book itself shows to take place during the homecoming related in the first book:
The Adventures of Doctor Dolittle.
The ending of this chapter is perfection as Bilbo from the height of the pass through the Misty Mountains sees for the last time in the book the Lonely Mountain far away on the horizon and wish only to finally be
home.