Toady do you picture the incarnate gods (Dragons, Titans, and some such) eventually being legitimate gods in their own right or just fakes that people latch onto?
Assuming of course you have a set idea for that at the moment
While I have my own idea of what they are, I am curious as to yours.
I'm almost sure these pose as gods or are worshiped as so, they are not really incarnate gods. Demi-gods adventurers are more related to gods than titans, I think.
I think the only meddling gods do now are curses.
I could be wrong, though.
Although they do get "worshippers" of their own during history, so maybe they are considered gods in their own right?
I can imagine a civilization that bases their religion off the great beasts and titans it has encountered, though how they would interact with giant flesh-devouring snails or huge murderous metal statues in any meaningful way might come into question, though one might say the same about the religions with more aloof deities - if you have a god of war, shouldn't you always win all wars? If not, are your gods turning against you? Is it any different if the god-snail destroys a town?
From the fact that people already "worship" the megabeasts (though not in any meaningful way), I would guess there is some eventual plan for religion to have this type of setup as a possibility, though it likely isn't any time soon. There's a lot of question about how active the gods will eventually be, or if they are to really exist as physical entities at all in DF, so presumably when the pantheons get looked at this sort of thing might come up as well as a natural extension of the end of the spectrum where gods are not only real, but actual physical entities you can meet out in the world.
What exactly will be the nature of Hill/Deep dwarves? Is it just a title for dwarves living in a certain area, or will there be a sort of subspecies system?
The way they have been described is just a categorization based upon what sort of sites they inhabit. While the deep dwarves will likely be more cave adapted, there probably won't be any biological differences (none have as yet been mentioned). It is likely that the two populations might end up with differing "genes" due to lack of mixing of the groups during worldgen, so surface dwarves and deep dwarves would end up with two different sets of traits, but this would be an emergent feature, and it is not known as yet if this will happen. It is also likely that hill dwarves will frequently have different professions from deep dwarves, due to different jobs being available at the two kinds of site.
There is currently no known system for forcing one caste to one site and another to a different site, and multi-race forts don't work at all right now, so I'm pretty confident in saying that they will all have similar traits, though if I'm wrong the Toad will correct me.