Well, I have a bit of a combat system figured out.Think Dynasty Warriors. You press the square button to start a regular combo, and end it with the triangle button to perform a variety of combos. I was thinking that you would get a skill tree, and there would be several different types of regular combos. You could also unlock a variety of ends to your combo through the skill tree, and you can assign it to a certain number of swipes.For example, I could buy the move "Poison Claw" and the string "Martial Arts." I can assign Martial Arts as my regular move string, and assign Poison Claw to C3, meaning that I press the square button twice and then the triangle button. (C1 would be pressing triangle without any string, C2 would be with one attack, etc.) I feel like this would really make the moveset feel like your own, since any combo end can be assigned to any number from 1-10 for amount of regular strings before triangle.As for your ideas:1: I think has been done before. However, I hear it was banned in America, so we are still without such a game, and it would make me reflect upon who I kill. I think a good example of what you are trying to convey would be a bit like Skyrim, but EVERYONE is killable, and if you kill an essential NPC, you either cannot do the quest or have to find another NPC to help you.2: Would have us reflect upon not judging by first impressions. Such a thing has been done before, but I think that it could be an excellent game if implemented right.3: Well, I think it needs some kind of quest and goal system, otherwise the game would become tedious. If I am anything to go by, gamers need some kind of direction as an incentive to keep playing. But, yes, this would have potential as well, though I like the other two ideas better.