This is just my opinion but your statement declaring that UC "slowed down" is false. Gringotts is everything you said it should be in your first sentence. It is a race through caverns, amazing set work, with a hint of classic winding roller coaster elements and fun effects. Just bc I agreed that it wasn't AMAZING (like FJ or SM) doesn't mean it was a low blow from UC.
They did not slow us down and they did not cheat. They had a story to tell and the only possible way of doing so was with screens. Ride the ride and see the way they mesh the screens with reality. At times I fully believed that it was all a part of reality.
Making statements such as yours, regardless if they remain your feelings, are ignorant simply due to your testament that you never rode. What Universal is doing now is keeping up with technology while keeping a foot in reality. Kong will be no different.