I’m a big fan of Miles’ work in the late 60’s and early 70’s; just ordered the Vinyl Me Please box set of Electric Miles Davis, which has his albums from ’In a Silent Way’ to ’Get Up With It’....
That’s one of the great things about Miles -- there’s something to please just about any Jazz fan!
I never developed the ear for the saxophonist’s individuality as you describe it, but I do have that ear for the electric guitar masters
It’s purely a matter of exposure/repeated listening. If you can tell the difference between P. Green and D. Kirwan, between EC and Duane on "Layla", between Andy Powell and Ted Turner on "Argus", you can learn to tell the difference between Sonny Rollins and Dexter Gordon. Of course, you have to like the music enough to begin with, otherwise you won't have any reason to put in the time for this process to occur.