Yo, as much as I agree Oryx was the better villain, I dont know that the "average gamer" really engaged with the Books of Sorrow and without that added context it becomes pick your favorite flavor of Saturday morning cartoon villain.
Likewise, with the different races, there is just naturally going to be a flavor your gravitate towards more; I totally get the love for Lovecraftian worm gods, though I could see how some people might engage more with the mindlessly homocidal Vex or militaristic Cabal for similar reasons.
I think the raid will give you a lot more of what you're looking for, since we know the author who wrote The Books of Sorrow at least wrote some similar stuff for the the exiled Cabal Emperor, and that the whole raid revolves around him and his world-devouring ship. Give it until raid stuff starts coming out and we see what kind of lore shit is attached to the equipment - I have a feeling you'll dig it a lot more than Ghaul's militaristic campaign.
Good post. I very much agree with all your points. I've seen some concept art of the Leviathan, and that seems right up my alley.