The reason for no major thrills above the ones we have is families. Cedar Point and Six Flags have their coaster and amusement niches, but there is a reason central Florida is the most visited area for themed entertainment and amusements. As a whole, its family friendly. I love a great designed coaster but a great coaster ride does not always mean pushing things to the limits. Like an action or scary movie it needs to be well designed and well paced. the 200 foot thing is of course in part to theming as well at times because you are required by FAA to have a beacon on anything 200 feet or taller for aircraft safety. They don't want a skyline of those.
Millions of people go to six flags and Cedar Point and other major thrill parks every year, but for the 100 million that visit Florida every year, they want to appeal to the wider audience.