I personally disagree with ESP being able to be turned off on the public roads. I also understand that ESP will soon be a mandatory feature required by law on all new cars (VIC leading the way), so an option to turn this off is really never going to happen... and even if anyone figures out how to do it, they probably won't let anyone know due to legal and liability reasons.
But what I would like to see, is for cars with Sat Nav, the ability to turn off the ESP when you're NOT on the public roads. So when you're on a private road, or race track, etc, you can turn it off then. Kinda like how the Nissan GTR R35 removes it's limiters when it knows its on a race track etc.