The thematic map brings out some oddities in the composition. The most important and interesting one concerns the "Embassy and Assembly II" intermezzo which at first sight is quite unlike the other E & A's. It is made up of three parts: Failure by Day, Embassy to Achilles and Success by night. The battles in the first part (book 8) seem rather redundant, while the night episode of book 10 is almost universally condemned as a fremdkörper. Its central episode however, the Embassy to Achilles, is very much a necessary part of the story.
First it should be noted that the end of book 7, what I call the "the people choose war" thema, is in itself an Embassy & Assembly part. There is an Achaean and a Trojan assembly and a Trojan envoy goes to the ships with the Trojans' peace proposal. So structurally the whole of books 8, 9 and 10 could be removed and the basic plan, the Chimaera model, would still be intact. The story could move effortlessly from the end of 7 to the beginning of 11.
Secondly, there is the "somewhat odd"-ness of the Deception of Zeus episode. Brilliant as it is and also well-placed poetically as a temporary escape from all the fighting and tension, it still feels a bit off-topic. We could almost be tempted to call it a digression. Then there are the famous duals in book 9 (Homer is using a grammatical form indicating two people while there are three, apart from the two heralds (Il 9.183-98). This error appears to leave stitches visible in the patchwork. I suggest the following solution:
Originally, the Embassy to Achilles was in the place of the Deception of Zeus. This fits: the Achaeans are desperate and send for Achilles. He refuses but a little later sends Patroclus. The poet (or "a poet") decided that the embassy had to be moved forward. Phoenix(1) was added to the ambassadors and the scene was partially re-composed. On a reason for this we can, as usual, only speculate. Perhaps he thought the poem went on for too long without Achilles appearing, perhaps he found the original sequence with Patroclus' death hard upon Achilles' refusal to fight, unsatisfactory. Too much climax in a short stretch of poem maybe so he decided to add a little water to the wine. But in the logic of the storyline the embassy would fit much better in the very centre of the poem. It must be noted that in terms of ring-composition, this fits perfectly.
So he decided to bring the Embassy to Achilles forward to a point before the beginning of the central Day of Battle. This created a problem for the poet who is always so conscious of the state of mind of the individual fighters and the armies. Like a sports coach, he knows that winning or losing in battle is for a large part "between the ears". At the end of book 7 and the beginning of book 11 the Achaeans are full of self-confidence. The events of book 7 and earlier have been no reason for desperation. The embassy however obviously requires that the Achaeans be in despairing mood. After the failed embassy, it would be odd if the Achaeans went to battle confidently as they do in book 11. So we need the Failure by Day episode (book 8) to switch from confidence to desperation and the Success by Night (book 10) to switch back to confidence. As for the structure: it should be noted that the poet is careful to weave a few assemblies into the added parts.
Other analyses are possible of course. The Doloneia has often been described as non-heroic and therefore non-Homeric. Heroes at war do not do such things. Or perhaps they do, but they certainly do not sing heroic songs about it. But Homer does, just as he sings angrily about the taking-women-in-revenge-for-Helen theme. This aspect of it makes the Doloneia very Homeric in my interpretation.
However: the theory that the Embassy to Achilles was moved from the centre to E&A2 and that books 8 and 10 were created to make the story fit, has a slight problem:
In 18.259 Polydamas appears to refer back to bk 8 where they are camping near the ships (Il
8.489-), saying: “I, too was (always) glad to sleep near the ships in the hope of capturing them”.
(the Butler translation is wrong. χαίρεσκον "I always liked to..")
(but: it may refer to Polydamas' advice in the situation of 13.726-)
Menelaos in 17.24 refers to a killing (Hyperenor) he did in 14.516, the Counterattack 2.
All this goes to show that if the above theory is true, it is not about a simple cut-and-paste but a partial rewrite using both new and older material.