From what I've read, heard, and seen over the years, I think Clapton has gone out of his way to acknowledge his influences (From The Cradle being a prime example in his discography but not the only one), and has never represented himself as nothing other than a student of the blues (my words not his). That said, I guess I don't understand all the hate etc. So the guy isn't totally original or particularly innovative in the blues genre-- no big deal in my mind.
Evertything up to and including his 1981 release Another Ticket is pretty interesting and worth a listen. After that it gets sketchy (Thanks Phil Collins!). My general rule of thumb with Clapton from 1981 forward is that if he's wearing a pastel suit that matches the color of his strat. on the cover of the album, you should pass.