I think the reason Crystal didn't get all the stuff that Lee did is simple - she doesn't want it.
I know Lee got the whole choir behind him but truthfully I am not sure that Crystal would have even wanted that. For all we know - she refused that sort of production for her song. I was thinking about how big the numbers are usually in the finale and I just can't see Crystal going that big. I would be willing to bet that at one point next week, Crystal would sit on the stage with her guitar and a single spotlight and that would be perfect for her. She is not into big productions. So to say the producers were unfair to her doesn't seem right to me. Crystal doesn't want all that. It is much more fitting to Lee's style of singing.