As a guy who plays guitar a bit I know that his album featuring Eric Clapton was earth shattering. On that album Clapton broke with the trends of the time and played an old Gibson Les Paul (which at the time were out of production because nobody wanted them) into a new-fangled Marshall amplifier and he CRANKED it. The tone he got and his aggressive playing made guitar players stop in their tracks.
After that the way guitarists played and what they played on changed and birthed the rock gods of the late '60s and '70s. Mayall did that. Then he brought in Peter Green and that's a whole 'nuther story but the punchline is "and they went on to form Fleetwood Mac". I have two of his records, the one with Clapton and the one with Green. Good stuff.
He did have a great knack for developing talent.
Did? sorry, I should say: still does.
Wasn’t just Clapton in the Bluesbreakers, but the late Jack Bruce too. Just like it was not just Peter Green, but also Mick Fleetwood and John McVie in that band.
Also featured in this band were Mick Taylor (more famous for his stint in the Stones), Aynsley Dunbar (too many to count, including Zappa’s band, Journey [original drummer], Jefferson Starship, Jeff Beck et al), even Patti Smith as a backing vocalist.