The Kennedy Center started giving their honors out in 1978, these wonderful artists passed away before getting one, some died young like Freddie Mercury and Kurt Cobain, Others like Dean Martin should have got one in their lifetime, here is a list of icon that passed away after 1978 that should have received one!
http://www.ranker.com/list/icons-that-died-before-receiving-a-kennedy-center-honor/craigalarm,
Alfred Hitchcock
Dean Martin
Dudley Moore
John Lennon
Mickey Rooney
Peter Sellers
Robert Altman
Robin Williams
Steve McQueen
Walter Matthau