Splash is much more than a standard off the shelf log flume...Space Mountain was anything but a low-end rollercoaster...it was a unique tubular steel coaster, double tracked, and woven together, completely custom every bit of the way....and then beautifully themed.
Star Tours is a simulator but completely reimagined to what was an off the shelf system... None of these are exaples of an off the shelf carny ride that had added theming.
"Themed" does not imply "completely unique".
The ride system for Splash is just a flume with a great show. The history of the ride was a reaction to other parks building flume rides and finding a way to "plus" it. If you strip out the show, whats left is basically a bone standard log flume ride system.
Space Mountain may have a unique tube structure and custom track, but it is considered a wild mouse coaster, which, even at the time, was not revolutionary, in the least. The theme, again, makes the ride special, not the ride making the theme special.
Theming up a custom built version of a standard ride doesn't make them a unique ride system, it makes them unique takes on very common ride systems. The "classic" Disney was all about taking normal things and making them better..."plus it".
When it comes to pure Disney innovations, you get into rides like Soarin', Test Track, Universe of Energy (more due to the novel trackless system), etc...
My point being that many of the classics that we all know and love where not unique ride systems, they were unique experiences built on familiar systems.
