When you think about it, he's really no less offensive than C3P0 in the original trilogy. All comedy slapstick and ridiculous voice, but the difference is the majority of us were children at the original trilogies release and embraced it all. I'll bet anyone who saw the prequel trilogy as a child, I'm talking twelve and under, will no doubt love it and look confused when you mention the hate for Jar Jar.
The truth is the Jar Jar backlash says more about the fans than it does about Lucas, Lucas made a kids film, it's his baby, he can do what he wants and it's been unfairly criticised by thirty something adults. Nobody had their childhood destroyed by the prequels, people ruined their own memories under a weight of expectation that was impossible to meet from the outset.
I personally still get get goosebumps when the doors open in the climax of 'The Phantom Menace' to reveal Darth Maul to Williams thunderous 'Duel of the Fates' and trigger one of the best cinematic fights of that decade, that for me balances out Jar Jar's slapstick and admittedly infantile warblings.
For me Jar Jar was simply a scapegoat of a bloated and over produced science fiction movie, with fleeting moments of brilliance. Has Ahmed Best ever worked again? Poor bastard, he's got five kids to feed!
Wait that's a different movie...