1) I'll leave night shows and parades out of this, because it's a seperate situation they've at least started to improve on.
2) DAK is the only WDW park that has stage shows worth a damn, so let's not act like WDW has a plethora of great live stage entertainment. Those 2 shows are amazing, but they're in the same park.
3) Universal parks are not Disney parks. They never were, they never will be. They just don't do stage shows well, as evident by the even worse new Beetlejuice show. They don't have the land to waste on trying and failing at what they don't do well. Replace weakness with strength, and improve your parks.
Besides, I guarantee a Ministry of Magic area would get people to stay in the parks longer than a stage show.