Open spot's:
Trade leader
Expansion Leader
Science Leader (prob. Pellaken)
and various deputy position's.
Note though that all these position's have changed though under the reformation's.Every leader will now make his own decission's rather than polling the people for it ,but the people have the power to override that if they get enough support.
Basicly it mean's that ,if you would do the expansion department (wich you have done before) ,you would not open poll's anymore on where to build a city or what region to explore ,rather you would decide in one thread (between every game turn's) wich area you should explore next and where to settle new city's.The tread would serve as information to the public ,and it would be one sticky thread and further nothing more need's to be posted ,unless the majority of the people disagree with you and then you would be forced to open a poll (wich wouldn't be very coman).
Same goes for the trade leader ,he would decide between wich city's trade route's would be established ,unless if he would be overrided by the people.