So you want completely new content and story... Yeah. That's just not realistic here. Not for Universal. And actually... Not really for any show with a reasonable budget.
You want them to celebrate the movies without showing the movies... Most people would probably differ from your opinion. For many, they have to see clips from the film to even know what the show was talking about or referring to. The general public barely know the films to begin with.
Original content is expensive. Original animation can be as expensive as $800k-$1mil per second. Live action isn't much cheaper these days with all of the post processing done to make films look "cinema-like." Making new media for shows like this wouldn't be any cheaper. You're still having the studio make assets that match the level of the films. By that measure, a typical show could be tens of millions in just media alone. Together with equipment and construction, that could make a show unaffordable very quickly. There is absolutely no way that a show like this can make a return on investment with media being that expensive, and for what? The existing films already provide a ton of previously made content that is relevant, recognizeable, and good. It's just up to the show creators now to do something creative with that instead of just playing clips. And playing clips alone isn't a cheap option either. Every time a clip is played, there are multiple royalties and license fees paid to the studios, creators, and actors featured.
The words "clip show" get thrown around in a derogatory way as if using film clips automatically makes a show bad. I completely disagree. While I want more than just clips on water screens, using existing clips in a new way to build a show seems incredibly relevant at a movie studio theme park. It doesn't make the show cheap or lazy, it's a creative path that can be done well or done poorly.
Somewhere, someone got everyone on a high horse about shows like this and made the word "clip show" a swear word. Think about it realistically, the criticism doesn't completely make sense.