I would buy the hell out of Total War: The First Holy War.
I always envisioned a game with Total War combat mechanics, but outside of battles, a more RPG/adventure framework, covering the manipulations, faction intrigue, etc. of the story. Kind of a good ground for "what if?" segments, where different avenues are pursued, different characters convinced to different degrees by varying means, etc. So you can have a Holy War led by Conphas, or with Conphas as Kellhus' primary devotee, or Kellhus dying on the Circumfix because Cnaiur died earlier on and can't slaughter Sarcellus, or a million other ways the series could have played out with different decisions on the part of the characters.
You win the game by keeping Athjeari alive through to the end.