I will only go to Theme Parks when I know it's not going to be busy (Overcast day or not school holidays). I wouldn't even consider going during the peak peroid times as shown in the article so this pricing wouldn't effect people like me.
I would also think charging more may make people wait till it's off-peak time to visit Dreamworld. Thus making making it less busier during peak times. But I would think most people would just arrive at the ticket gates and then be hit by the price rise un-knowingly.