So... A screaming orc in armor and a woman? Maybe there'll be some feature to let us choose a race in character delection. I'd love to play as a lizardman or elf (especially given how conspicuously absent they are from DOS).
I really don't expect a day/night cycle for original sin - ever. It's a ridiculous amount of work with little return for it at this point. I would like to see one in Larian's future adventures when they can design for it from the start, but retrofitting D:OS for one now is one of the least likely things I can imagine them doing.
A day/night cycle would actually entail very little work and could be done fairly quickly. I think you're confusing day/night cycles with NPC schedules, which are two very different things.
Day/night cycles would simply make the world more dynamic--both visually and in terms of ambient SFX.
A well done night cycle would actually still be quite a lot of work, because each individual zone (e.g., the fire zone in Cyseal) would have to have three or four different atmospheres specifically designed for it, and there's a number of issues to overcome with regarding zone tranfers, saves (how to remember what atmosphere you have), and other problems with making sure the player has the right atmosphere. Maybe Larian could pull it off in less time than I'd imagine, but either way Swen has said he doesn't want a day/night cycle without NPC schedules anyway, which is a huge amount of work.
Day/Night transitions are pretty awesome for sure, but they lose some immersion when everyone at the marketplace is standing around selling wares at 3 AM.