For what it's worth from me, no, "Rebel" isn't that great despite Dean's
rep and end and depsite director Nicholas Ray's high-auteur status in some
circles. I find some of it almost expressionistically silly, much of it
just melodramatic.  But it does have a kind of earnest style all the way
through, and I think it simply tapped into a youthful zeitgeist of the
time, so it became a kind of cultural text.  This one was released slightly
before my time for watching films of that ilk--but that makes me realize
we can't quite see it in the same way as someone from the time, and can only
get close to that through imaginative sympathy primed by some scholarly
apparatus.  This is really a film *of* its time primarily, though it has
a unique and rare display of Dean's acting craft that's kind of detachable
from the film if you prefer to view it that way.