I don't think he's considering Cleveland because of their roster, it doesn't have much to offer yet. Kyrie and Wiggins are pretty damn good, but they aren't seasoned veterans and they just got a rookie head coach. Now, I think it's more for the legacy of returning to Cleveland and because I believe his family said they liked Cleveland.
Miami is an aging franchise, but they're still his best bet by far if he wants to play for a ring. If he rejoins Cleveland, they probably still wouldn't be the best team in the East until Kyrie, Wiggins, Thompson and Blatt can blossom and show up which I don't think will happen just yet.