Change the way politics is geared to delaying a Civil War to making it geared towards preventing a Civil War.
Add a slider bar or similar graphic that shows where you are standing re possible Civil War. Green and you are safe and incrementally through to red where Civil War can occur.
At the moment I really don't know where I am regarding Civil War. Is it Gravitas, is it the number of senators??? All I know is it is going to happen at some time no matter what you do so why bother with it.
But if it is preventable, it makes playing politics worthwhile and would add that extra dimension to the game.
If you can see where your standing is, you will do something about it. If you are teetering on Civil war, you will move that popular general to a rural backwater, even if he is your best general. You will do all of those underhanded things to keep Civil war at bay and move the slider into positive territory for you.
CA could add random events which effect the slider, such as one of your senators killing a rival - slider moves a couple of points towards Civil War. Time to scramble to redress the balance before it is too late.
Your action in politics can effect your campaign play such as taking a public order hit for removing that popular general.
The actions you perform in politics would not be automatically performed (marriage-spread rumours-assassinate) but would be attempted similar to agent actions and you should suffer a politics hit if you fail. You could even employ your agents to increase your chance of success.
If Civil War does occur, rather than the AI spamming armies at one location, they could spam an army in each province at the settlement that has the lowest public order.
And the bigger you empire is the harder and more expensive it would be to maintain the balance. This would act as the anti steam-roller factor in the game.
Well that's my two cents.