Well I have to say that if every slot on an island has to be filled, even with new builds it's a waste of time building them and a serious flaw in thinking. It also removes the grey flag farms from an island and reduces resources, not good!
Who in thier right mind would build a new city when you could just conquer one?
Anyone who has 3 or more cities would never want a new build, ever!
I think this needs some serious revision. You should have control over an island with only your alliance cities on it and maybe 4 cities on that island to build a wonder.
What will happen is that we will be scrambling to make 'turtle' islands to build wonders and no one will be attacking anyone.
Also, with a 'turtle' island it is almost impossible to make a conquest of a city, once again a serious flaw but only noticable by those who play.
Come on dev's you can fix this, make it 4 cities per wonder and the island under the control of the alliance. That way everyone will have a serious chance to build one and more important to attack those being built and make conquests on the island to stop it.
Storm