The politicians could grant upgrades that would only be useful at the end of the game and would require a fourth resource to use it in the capitol, church, armory or university. In addition, only one of these benefits could be used at a time.
Depending on which politician you apply, you will have certain benefits, but you can alternate just like in the Asian consulate.
It would be a good way to balance it out and make better use of politicians to provide permanent benefits.