That would have helped, yes. But it's a very difficult system for a PID controller to handle, because there's a big discontinuity around the equilibrium point. If you assume 100% perfectly rational miners that will instantly switch to the most profitable chain, it basically becomes unstable, no matter what you do. It's like trying to balance a seesaw with a 100-ton steel ball that wants to roll to the lowest point.

You can only get stability by relying on miners that stay on the less profitable chain. But as time goes on, I expect miners to come up with algorithms to automatically switch to the more profitable chain as quickly as possible, which is going to make the problem harder and harder. And the more violent swings, the more miners will be tempted to switch back and forth.