In my personally opinion I think ideology is far too cheap, and they dont stack very well. e.g. if you are going for a benevolent race it should also make all other ideologies harder to get, this way it should discourage you from trying to get all 3 ideologies.
In my current game, an immense map turn 266, I have now maximised Benevolent and Malevolent and half way to maxing pragmatic. This to me seems like ideology is far far too cheap and can easily be maxed pretty damn fast, especially for colonizing spammers - like myself.
Maybe there should be a rethink on the cost of ideology stacking? Or maybe a rethink on cost per ideology depending on map size?