I assumed people were thinking more Tron or Hagrid's (48", ~7 to 8 years old) and less Hulk (54").
I did a search of "Hulk" in this thread and found nothing related to Wicked, at least not recently. Was this specific suggestion posted somewhere else?
I think at least part of this conversation comes from the idea that the land can only have 1 major attraction. I think Wicked could work with a coaster and a dark ride, similar to Hogsmeade. (Or a coaster and show, similar to Berk.)
Regarding this being the "Disney Princess" of Universal, I'm not sure where that is stemming from. The source material is from a musical play that is not really targeted towards children, which is from a series of edgy books meant for YA+. Oz as a franchise is all ages, with Wicked skewing on the edgier and potentially older side. The movie itself does not seem to be marketed as a children's movie, but instead for all ages.
Unless I'm seriously missing something, Wicked is not really "for" young children in the same vein as other children's movies. If I'd guess, it's generally for preteens (e.g. 10-12), teenagers, young adults, and the young at heart. That's probably why they cast Ariana Grande, the singer of 34+35, which is not a song about kindergarten level mathematics. (That last part is a joke - they obviously cast her for star power.)