As has been said before by myself and others it really is the HOF of Popular Music. As such Neil Diamond and Laura Nyro should both get in as songwriters and performers even though Laura Nyro's career was cut tragically short. Among her compositions: Wedding Bell Blues, Eli's Coming, Stoned Soul Picnic, And When I Die, etc.
Alice Cooper is long overdue, his music has aged better than most of his contemporaries. Plus his invention of the "Shock Rock" stageshow, which has become an arena rock staple, helps cement his legacy. The band had a major influence on the development of heavy metal music and can still be heard today.
Dr. John's contribution to the American music scene cannot be underestimated. From stalwart New Orleans and Memphis session player, his "Night Tripper" alter ego, (think "Walk on Gilded Splinters") and successful mainstream hits, "Right Place Wrong Time" & "Iko, Iko" still get airtime. Dr.John helped repopularize New Orleans music, the city which truly is the cradle of all American music. Producing, session work, performing and preachin' about, jazz, blues, funk and rock, "The Doctor" has done it all.
Of the 500 odd concerts I have been lucky enough to have seen, the first Dr. John & The Louisiana Luminoids show I saw at the Village Vanguard ranks in the top 10. 'Sho 'nuff!