For me, 5.8 is a big improvement over 4.5, and the suspension thing has not impacted me in any way over the past few days of highway driving.
Having said that, I think updates should be optional (to a point) and there should be some sort of rollback capability. I can see the need to keep withing, say, one or two release versions or it would just get too difficult for Tesla to manage.
I honestly can't tell the difference after the update. It's not like the higher setting disables the car and keeps you from taking road trips. Yes, it you were planning a 265 mile trip on level ground all on the highway at 65 mph it would make you stop and charge maybe unless you could drive 60mph that is.
While they can 'take away ' features they also can add them and lots of them without having to go to the dealership like you would with any other car. Both positives and negatives with this feature I guess.
I really think a petition is an over reaction and wouldn't do anything useful anyway. I'm sure they know some people are upset already.