Besides the declaration of war, there's nothing in 2.35 to support a First Punic War scenario. Something else I've done which will be in the patch is switching the AI stance when a scripted declaration of war happens.
The problem with the current situation is that while the diplomatic status may change, the CAI is still looking to make peace as quickly as possible. So the war situation is only temporary, and the AI doesn't actually behave any more aggressively.