Who said it has to be Unique? As long as its new and shiny it will get peoples attention.
I would think that it should be considering it is replacing a very high profile ride that was itself very unique even if it was a failure.
I dont think it needs to be unique though, I think we need a new coaster with some loops. Kings Island has only added one coaster that has had multiple loops in the last 13 years and that was Firehawk.