>complex system (BG 2, pathfinder wotr)
>gooning (mass effect, ff, bg 3)
>insanely large game/story (bg 3, pathfinder wotr, ff, roguetrader)
>being an op godlike king (pathfinder, ff, bg2 throne, roguetrader)
>a clear vision what the game is about (see all of the above)

Why is this so difficult for other devs? (cough dragon age cough)