I'm not knowledgeable at all about Sheena Easton, but when I think of musical versatility, I think Linda Rondstadt. She could do and did rock, pop, country, jazz, blues, and opera effortlessly. And her emotional interpretations of the different genres is what every vocalist strives for.
Michael certainly knew how to vocally interpret a song. I think that was his greatest talent-
Her American Songbook trilogy is right up there with Off the Wall as my favorite albums of all time. Oh, and she could act too. I really discovered her with "Pirates of Penzance".
Speaking of Sammy, I always loved him from tv as a kid, but I got the chance to see him live in my early 20's. I went in as a big fan, and left the arena a screaming, raving, hysterical FAN.
I'd never seen anything like that before. He could do anything. Gorgeous voice, tell jokes, be poignant and heartbreaking, impersonations, dance-just amazing.
Michael chose truly great performers to admire and to study.