1) In the past, I had actually considered such a game, but to make development easier, I'll probably won't have a path where you stay human. Also, I'd like for this to have a very specific mythology, and the various monsters you can be turned into (vampire, werewolf, demon, etc.) would work as clans in bloodlines, and actually have a unified "origin story" of sorts (so myths and legends about these creatures are mostly made up by humans, who don't understand the truth behind them).
2) Well, it would be the kind of gameplay where you will, for example, find a locked door at one point, then later on find the key, and be able to travel back in time to open that door, for example, or with information you learn later on, unlock actions in the past, and so on. It would work like a visual novel mixed with a point and click game, more or less.
3) In a sense, yes, although it does have some fighting as well (I imagine the most "RPG-like" element of the game would be going on expeditions, to secure areas overrun by monsters, and find "resource nodes" in those maps as well, and then you can use those resources for expanding your base, create new equipment, potions and so on. The setting would be a secluded city, the only known survivor of a catastrophe during which monsters have overrun the world, and now are slowly trying to take back areas outside the walls, with these expeditions.
As as I said, though, I do have more ideas and details, but I should stop here. I have games in the making to worry about, before I start thinking about other stuff. XD
