I know this is a MTB cassette but is SRAM intending to do something similar with their road cassette ...
PS: Here's a bit of info on the RD ...
SRAM XX1 11 Speed Rear Mech Technologies:
- X-Actuation - Designed specifically for SRAM XX1, X-Actuation keeps shifting sharp and consistent across the entire 10-42T cassette.
- X-Sync - A "wide tooth, narrow tooth" pattern is repeated around the pulley wheel, perfectly mirroring the chain's inner and outer links for maximum control.
- Cage Lock - With Cage Lock, wheel removal and installation - becomes faster and simpler. Just pushing the cage forward to create slack and lock it into place.
- Roller Bearing Clutch - Roller bearing clutch technology eliminates derailleur bounce and chain slap without sacrificing precision.
- X-Horizon - Straight parallelogram design limits all movement to the horizontal axis, which makes ghost shifting impossible while also reducing shift force. For quicker, more exact shifting, the large upper pulley offset design maintains a constant chain gap across all gears.