Oooh, a spreadsheet. Do you mind if I ask how you've organized it? It sounds more efficient than a simple list in Word like I have.
Not at all! I started with a list, but by the time I got to my sixth world state that was getting incredibly cumbersome.
It's a simple set up - I've got a column for each significant decision, and each different world state has its own row. So, for example, one column says "Orzammar" and has a note on who became king, and another says "Anders" and explains what happened to him in a given play through. And so on and so forth with every important quest and character in Origins and DA2. (Or, rather, each decision I'm guessing will be important. I imagine I'm going to end up adding and subtracting stuff once I get a look at what's actually in the Keep.)
What I really like about having a spreadsheet instead of a list is the ability to hide things when I'm not using them.