Yes, I played Rome II with a few mods before the update and I'm still doing so. I'm sorry to hear that your AI mod no longer works. In case you want to try it -
A More Aggressive AI by Turquoise Falcon (the one I use) still seems to work (either it is working or the AI is more aggressive than it was before.) I don't see the mods as 'fixing a very poor update' - I use them to fix issues with the base game, not the update.
You wrote that the update "didn't fix any issues the game had/has". It did for me:-
1. The user interface was uncomfortably small on my screen and could not be scaled. The Power and Politics patch fixed this.
2. Planning character development was a bit harder when we couldn't see the skill tree. The patch fixed this.
3. The poisoning skill for agents was overpowered. The first time a high-level agent poisoned one of my armies, I felt as if it had suffered an air strike. The patch improved this.
4. Grain settlements were overpowered; after capturing a few of them, I no longer needed to consider food when upgrading buildings. This was fixed.
5. Previously, I didn't see a civil war; people who did see them tended to say that the rival side owned a rather random set of regions scattered across the empire. With the new system, I saw a rival family break away with a province. For me, the new system looked more like historical civil wars (such as the ones in Imperator Augustus and Empire Divided as well as the Succession Wars of Alexander's empire). In my campaigns, the new politics system does add to the game: events on the campaign map have an effect on politics and politics can have an effect on my decision-making.
Obviously, I know that others have different preferences - some players might have preferred the poisoning effects and the effects of grain settlements as they were before, for example.