The Centrum is a round open cage. The Gravitron is an enclosed UFO/flying saucer that spins and gravity pins riders to the wall. Two different rides, even though they both spin. Centrum has an option to rise to a 45 degree angle as well as spin flat without rising.I see.
But honestly that sounds very similar to the centrum...
So I still I don't get the point of asking for slight variation of existing rides in the game.
There are tons of rides out there that would be completely new in the game and would add a real value.