Keep in mind this will be the only game like this for dom3, so consider this a sort of test game.
If I find aspects that I think significantly make this sort of game less fun we will get rid of it for the next megagame. For those people that think something is unbalanced/unfun I invite you to join this game and prove your point. If you succeed you have my permission to then mercilessly mock those who disagreed with you.
Micah - Personally I totally agree with you. I find clam hording to be a remarkably unfun part of late large dom3 games. So much so that I generally don't pursue that path myself even though it gives great advantages.
Unfortunately though clams have always been a central aspect to late dom3 and dom2 games. The established players are used to this and accept it - some even like it. I don't think there will be much traction for changing this, especially since this sort of game is so unknown.
I will say that with the victory conditions there will be a fine line between over-hording and normal hording. %65 of the provinces is what's needed to win, so if a player sits too much on his *** without expanding he will fall behind. Turtling will not work in this game IMHO. You might be making a bazillion pearls a turn but if somoene on the other side of the world is expanding much quicker you are wasting your time.
That said, I'm sure the winner will have some trick going on - like Utterdark, Arcane Nexus or Clam Whoreding.