So inverse kinematics in Cry Engine is a performance-killer. I know because MWO had to turn the feature off, and when PGI (a small, third-rate developer whose single, awful game stays afloat on the strength of nostalgia for MechWarrior and BattleTech) needs to drum up excitement for a future patch, they make an empty promise about being able to turn IK back on without tanking framerates.
Yeah, CIG has now sufficiently debased themselves to invite comparisons to PGI, despite having enough money and employees to buy and populate an island in the Pacific. That's pretty sad.