I identified a major shift that was causing a major upward power deviation among the top two quantiles, asked what happened at that point, and proposed solutions to ameliorate the effect of the issue. I was told they had thought of all those ideas, and tried some of them with some success, that they were not allowed to try others because of the cost to test them or an anticipated level of transparency to the paying players.
I think the key in generic questions like this is to be careful to cover the fundamentals, and to be familiar with all the followups so you're prepared for whatever they throw at you. Maybe do a mock interview with one of the Zynga Game Designer experts on PrepTick to get a real-world answer? They give lots of guidance and pro tips on how to deal with this kind of stuff. https://www.preptick.com/practice-interviews-swe