This is a question I've long being wondering about. It might be a generational thing (I was born in 1990), but I remember when I was young that I would see a big Roger Rabbit presence in Disney parks (I had these Disneyland and Disneyland Paris Sing Alongs), this is also proven by elaborate rides as CarToon Spin and plans for other RR related rides for several different parks.
When I was young, I never saw the film as my parents considered that it was not a "kid's movie". I recently watched it and I agree that it has some more adult elements, and that it was not particularly child friendly. Why did Disney made such an effort trying to put so much of the franchise in the parks (apart from the obvious answer "to sell merchandise". I dont think that RR has aged well as a character, and I find that CarToon Spin is a bit irrecognizable for kids now. Did Disney think that RR would become a timeless Disney staple? Sadly it hasnt proven to be the case, IMO.