An open world Game of Thrones RPG. Use something like the S.P.E.C.I.A.L. System from the Fallout games. Skill checks in Dialogue, for lockpicking, etc. Choose to be a noble, thug, priest, spy, warrior or whatever. Your aim is to someday sit on the Iron Throne. You can help, stop or betray people in your quest for glory. People will do the same to you, depending on yuor interaction with them. Possibility to create armies and take over places like Winterfell, etc. Large scale battles, assassinations and secret meetings are part of your life when you start to gain power. Attend meetings with different nations. Negotiate, threaten, taunt (and much more) during meetings. Cause nations to attack eachother with skillfull deception.