This is mostly my point. I have two kids who love WDW. Both the parts with characters, and moreso the parts without. You loved Pirates before Jack Sparrow. Somehow, it was still fantastic without him. I loved Haunted Mansion as a kid, even without any characters.
No one wants to remove kids from the parks. If anything, my point has been that is the parents who direct their kids towards anything recognizable as a kid approved product by default. But kids have far wider interests than that. They want adventure. They want to enter fantasy worlds, and see fantastic things. A kid can love Rivers of light just as much without characters as with it, if it is a good show. So, why tack it on for no reason?
If the attraction is engaging and sparks the imagination, kids and adults will love it regardless of whether they are already familiar with a character that is used within.
That sentiment, is why many fear the parks will all turn into one homogonized mass of Magi Kingdom-like sameness. Disney isn't a theme it's a brand. When I go WDW I want to enter worlds. Find myself in the future, the old west, the jungles of Africa, or a Alien Space Port, not find myself in the Walt Disney advertising catalogue. Those IP's are welcome if the theme and attractions are built to use them seamlessly (fantasyland, Avatarland, Star Wars land, etc...). But when you tack them on as a lazy attempt to breed familiarity, it lacks imagination and creativity, and makes the entire park feel like less of a transportation from reality and more like a trip to the mall to look at things you know you already like.
It is a product of our current entertainment culture. Its the same reason why most movies are sequels, adaptations, or reboots. Businesses are risk averse, so they create a climate where they only offer you the familiar, without creating anything new to ensure your interest. But in the end, it's a cow chewing on its cud. Regurgitating the same mass over and over again until there's nothing of value left. When the parks cease creating new things and only reuse what we already know, they cease to be essential on their own merits.