FH since you always seem to be so concerned about VRS and A-VRS why don't you take the time to go AHS and read the following papers:
-V-22 Low-Speed/High Rate of Descent (HROD) Test Results
-V-22 High Rate of Descent (HROD) Test Procedures and Long Record Analysis
-The Nature of Vortex Ring State
As to whether the V-22 has a cockpit warning device I do not know. However the ROD limits imposed on the V-22 are the SAME as for every other helicopter in the USMC fleet. If you review the above papers you will find that with those limits, the V-22 has as much or MORE margin between the limit and VRS onset then do the helicopters. Currently helicopter crews honor those limits through crew coordination and by using established approach profiles, both in peace time operations and combat just the same as a V-22 crew does. Why do you imagine that a V-22 is more susceptible to a VRS incident then is a helicopter given the above information? Given the above should all helicopters have a VRS warning? How is it you have managed all these years to avoid VRS without a cockpit warning device? How many hours have been flown since the Marana incident and how many A-VRS mishaps have there been? The fact that the aircraft is being flown in combat as we speak and they aren't falling out of the sky due to A-VRS might be a clue.