We love and are fascinated by the Odyssey for all of the reasons you listed and more. Odysseus is an archetype and his journey is one as well. The return home is one of the most frequent narratives in history. We love Odysseus's return home because of the stops he makes along the way. But I think you are most on point in why we Love The Odyssey when you ask about its framing mechanisms. The Odyssey is still a go-to and will always be a go-to in the Western Cannon because of the tribute it pays to the art of storytelling. The layers of the story are so intricate that we designate it an epic. As we read become entwined in the complexity of the characters and the realness of the story. (A realness despite the myths and fantasy aspects)

Above all we read the Odyssey not because of the journey and not because of the hero, but because of Homer. The blind bard behind the characters is the agent that instills life into the story. The story is entirely dependent on back-stories. Every small obstacle and every side character is given magnanimous attention of detail. This level of description and background information gives the immediate story more splendor and meaning. The Odyssey is the first sequel of all times and perhaps the best. The Odyssey is an independent work that would never have existed without its brother the Illiad, a point which Homer often reminds us. The journey home would never have been required if the Trojan war hadn't taken Odysseus away from Telemachus and Penelope. In fact, to get caught up with the action of the Odyssey we travel through Telemachus who relates the stories of all the heroes following the end of the War. Somehow it feels that if we didn't figure out what happened to Nestor and to Menelaus we would never even have found Odysseus at all. Somehow the significance of his return trip would have been lost had we not visited his allies and seen that they made it home safely.

The Odyssey is much like Mark's description of the hyperlink. You can't go further than a line before you see a name or a story that trails off to a whole name or story or even a universe. Is it any wonder that the length of the poem is filled with bards and recounting tales of the War and the Gods? The Odyssey is an encapsulation of the entire mythic tradition. It is not just Odysseus, it is not just Penelope, and it is not just the archetypal return home, the Odyssey is the stories of stories. Inside it's pages lies every archetype, every literary tradition, every trope, motif, and theme. Why? Because it is filled with those hyperlinks that backlog every myth in order to give more meaning to the current one.

You ask why The Odyssey is continually reworked. Well, it's because in doing so the author is continuing the tradition of story telling. He is adding to the myth of Odysseus. He is adding hyperlinks to the text to increase the backlog for all stories. The Odyssey is the wealth of the literary tradition much like Robert said Wikipedia has the wealth of the human knowledge on it. By adding your own continuation of the Odyssey you bring new meaning to both your own text and to the original.

It's a question Keats asked too; until he found the translation which spoke to him.

MUCH have I travell'd in the realms of gold,     
  And many goodly states and kingdoms seen;     
  Round many western islands have I been     
Which bards in fealty to Apollo hold.     
Oft of one wide expanse had I been told
  That deep-brow'd Homer ruled as his demesne:     
  Yet did I never breathe its pure serene     
Till I heard Chapman speak out loud and bold:     
Then felt I like some watcher of the skies     
  When a new planet swims into his ken;
Or like stout Cortez, when with eagle eyes     
  He stared at the Pacific—and all his men     
Look'd at each other with a wild surmise—     
  Silent, upon a peak in Darien.

And notice what, exactly, happens. He describes this moment of revelation, the moment when he finally understands the clarity and brilliance of the text, by appeal to two images: an astronomer discovering a new planet, and an explorer discovering the Pacific.

Both the astronomer and the explorer are actively engaged in searching. They may not know exactly for what; they might be optimistic or skeptical of finding it. They are worldly and experienced people. But they have, in some sense, staked something serious on the search. For Keats, the encounter with the masterpiece isn't wading in the Pacific: it's seeing it for the first time. Speechless with possibility. In the midst of forbidding territory, you come across a map; you find a clue; you may still be in the middle of nowhere, but everything has changed.

Beauty and craftsmanship can be more easily appreciated, but I'm not sure that one can try to judge a map unless one has been in the wilderness which it describes.

(Still, looking idly at maps is an excellent incentive to exploration.)