For one, its boring and unengaging within just 2 hours of it's own runtime.
Secondly, the constant reuse of unconnected to loosely connected drone shots and blatant pulls of the same ABC Neverland Tour footage, about 10 images of the claimants with Jackson (despite supposedly having been connected to him for years and would obviously have more photos than just those reused), and the out of tone overlays of This is It on the Neverland Theater Screen and Adolph Hitler in a television set makes the information come across as specifically doctored to come across as "more emotional" than what it actually is.
And that isn't to speak on the many factual fallacies and contradictions that came out in both of the men's accounts in terms of timeline and consistency considering their own lawsuits and depositions against the MJ Estate, which obviously makes their already suspect claim turnaround as adults in 2005 more unbelievable as more details are revealed.
So, in conclusion
Leaving Neverland is an unengaging, subjective, and unreliable source of information that likes to pretend to call itself a documentary when it's really just a emotionally manipulative propaganda hit piece.