We've talked about it on here before. Disney doesn't seem quick to push their Disney Junior Shows into the parks .. if at all. My guess is that it probably is a licensing thing.
I am not sure if shows like PJ Masks, Vampirina, Puppy Dog Pals, Sheriff Callie, Goldie and Bear and such are full "Disney" properties (unlike the Lion Guard, Elena and Roadster Racers -- which you see in the parks). So while they can sell merchandise, maybe they are limited on character meet and greets? Or maybe they just don't want to invest in costumes for shows that may only last a season or two. The audience for those characters is short-lived.
Still boggles my mind that "Miles from Tomorrowland" never got anything in the parks despite the show being based around the fictional TTA (Space Mountain). Too late now as my son has moved past that.
As someone who has taken a preschooler to WDW a few times, I think they could use more Disney Junior stuff in the parks. My son (when he was 3) LOVED the Disney Junior Live attraction (was a bit scared of the characters though in person (they are so large to little kids)-- so that made the H&V character lunch challenging .. heh).
For us, though, that Disney Junior attraction was the highlight of the trip for our little 3-year old as he was really into all four of those shows at the time.
I think the parks could really use a Disney Junior section .. a no height-restriction ride .. the Disney Junior show (updated) .. meet and greets and a playground (the other highlight of that trip was the Honey I Shrunk the Playground). Maybe they will take the animation courtyard and transform it to that once the Star Wars Launch Bay is retired.