Here's the deal with Journey into your Imagination.
When Epcot opened in 1982, there was a ride called "Journey into Imagination" starring a characternamed Dreamfinder and his friend, a little purple dinosaur named Figment - voiced by Billy Barty. The ride was pretty popular but was falling apart, and getting tired after about 15 years or so, and they decided to give it a rehab, and totally change the ride.
Figment and Dreamfinder were kicked to the curb. The new ride, "Journey into Your Imagination" was horrible - it lacked imagination, creativity, a plot, or any cool effects. Michael Eisner rode it before it opened, got off the ride, and immediately said "We need to make some room in the budget for the next version of this ride. This was horrible." (Smart Move)
They decided to bring back Figment - who people were crying out for because he was pretty much the symbol of Epcot for the longest time, and then they just cut him out.... people were angry. But Billy Barty had passed away, and they needed someone to do the voice for the 3rd incarnation of the ride.
Enter Dave Goelz. This was about the time Mickey was courting the Muppets, and they probably hired Dave as a way to butter up to the Hensons. They could have hired ANYBODY to do a high pitched voice - they've got a stable of squeaky voiced characters, someone can do it that's already on their payroll. But they got Dave.
And now you know the rest of the story. Good Day!
Jeremy