The generation of jazz muscians that were at their height in the late 50s and 60s is almost gone. McCoy was the last of the so called classic Coltrane quartet to go. The last time I saw him was in Hartford in one of the jazz concert series that Jackie McClean's wife Lorraine organized. MCCoy was great with 'Trane with that heavy percussive style of big blocky chords but preferred his playing post Coltrane. I'm really sorry that we have lost his voice.He was brilliant. One of the last from the greatest generation of jazz.
Here's a nice article that discusses just that.Some say McCoy and Elvin were the driving forces in 'Trane band.