I think that games should have a few really obvious decisions however they would not be the game deciding decisions. Big decisions would be in a morally grey area. A good example of this is the save the council decision in mass effect. You can save the council, however this will cost immense human lives. For this decision if I am not playing through for the paragon achievment I always let the council die. This is because if I consider it from sheperd's point of view I would save all of my forces for the attack on sovreign, so that I would have the maximum chance of success. But I always feel sort of bad afterwards because I let the entire citidel fleet get owned and the galactic leaders die. One of the best decisions I have seen yet.