I would have to say
Occult- i would love that style of rp and political layers in an ap culminating in a trip to the akashic record to rewrite history.
Underdark i would love to see how the underdark unfolds in Paizo world
Planeshift an Ap centered around players plane shifting ( to be fair this could be combined with occult)
Bleached an ap following or touchung on a bleached gnome