Rock musicians with musical education.

Not clear to me whether OP is suggesting a university degree is a "better" approach to musical education or whether more "complex" (Prog, Fusion) forms of Rock are "superior" to simpler forms. "Musical education" need not be in a classroom environment. 

I've seen interviews with Jazz masters who've lamented that the university path is inferior to the old "apprenticeship" approach, where younger players learned by playing night after night on stage with more seasoned players. 

Clapton's musical education consisted largely of spending untold hours with a guitar and record player, going over and over solos by Chicago and Texas blues masters, laboriously learning their licks, note by note. In his case, given his interests, this was an excellent approach.  

The level of technique in guitar-playing has come a long way. For my tastes, this has not necessarily been a plus. I'd rather listen to someone who actually has something to say play three notes than sit through blizzards of notes by someone who possesses great technical facility but has not learned how to translate their life experience into something universal.

Chops and sophisticated theoretical knowledge are great, in the hands of an artist!

To my ears, the rise of guitar schools has resulted in a surfeit of hot-shot fretmeisters who haven't a clue about art. Needless to say, each to his/her own.  

... not that young hot-shots can't mature into fine artists... Ritchie Kotzen's a terrific example. Check out his Live in Japan live video on youtube. The chops are now in the service of something much greater. 

There is always the school of hard knocks.

The school of hard knocks will always be relevant.  Actual performance experience is necessary no matter how much innate talent a musician has.  Having said that, while it has become almost "in vogue" to suggest that a formal music education somehow diminishes a player's potential, even a liability, as a true artist nothing could be further from the truth.  Of course, there have been great players who, for a variety of reasons, became successful and reached a level that can rightfully be called artistic without attending a conservatory, a formal education can add immeasurably to a player's potential.  Also, keep in mind that a "formal" education can be pursued without attending a conservatory.  Many great players have studied privately and extensively outside of a "school" setting.  

Since mention has been made of Jazz guitarists, guess what all of the following have in common?  All attended music conservatory.  A small sampling:

Pat Metheny

Jim Hall

Stanley Jordan

Ben Munder

Emily Remler

Bill Frisell

John Scofield

Kenny Burrell

Herb Ellis

Kurt Rosenwinkel

Mike Stern

Al DiMeola

Julian Lage

Larry Corryel

John Abercrombie

Peter Bernstein

Larry Carlton

Schooling can help one develop one’s inate talent, and understanding theory---however learned---can help make a better musician. But remember, Danny Gatton was completely self-taught, as is Ry Cooder. Of course there aren’t many Gattons and Cooders walking around.

Musical taste is a whole ’nother matter. Learning what NOT to play is just as important as learning what TO play. I’ve heard a lot of technically advanced players whom I don’t consider very musical.

To hear the member of a Rock Band who possesses and displays a very deep musical education, listen to Garth Hudson’s extended opening in The Band’s live performances of "Chest Fever" (referred to as "The Genetic Method"). Classical, Jazz, R & B, Blues, Hillbilly, Pop--he knows it all.

Old musician joke: "Do you read (music?)". "Yeah, but not enough to hurt my playing."

Now, name any formally-educated songwriter you care to cite, and compare his or her compostions with those of, say, Brian Wilson, Paul McCartney, or John Lennon. Whose songs do you prefer? Education cannot transform modest talent into genius. Studying J.S. Bach's compositions will help one understand them, but not necessarily how to write like he.