Fair point. I was just thinking in terms of stability. 10 speed was definitely the redheaded stepchild of drivetrain development. I feel that with 8 speed you could definitely have a normal gear spread and then a DH gear spread that would work fine. I find with the 12 speed the steps are too close and there isn't enough of a discernible difference.
While we are at it can we get Shimano to loosen up on their double shifting? I miss that feature with SRAM components.