A head and blades that can't slice off the tail or cockpit, or a tail and cockpit that can deflect blades.
A capsule style composite cabin that separates from the frame in a major impact, rather than be integrated into the frame so it is crushed by the gearbox and engine.
A fuel bladder that is exterior to the frame so it too can fly off and roll away in a prang.
Nice but not possible; an ancillary independently powered device to correct a spin caused by loss of thrust from tail rotor.
Mickjoebill