Personally I don't like McCallum. I can't quite put my finger on why, but he strikes me as an ass kisser. I don't see what his purpose is other than to say, 'yes George' to everything. I know he's producer, but really. Isn't a producer supposed to keep a director sort of in check instead of just agreeing with everything?
Luke, the 'Jar Jar is the key to this movie' line is in referrence to the CGI work. What was meant is that if they can pull off Jar Jar, then they were home free as far as the rest of the CGI. Anything after Jar Jar would be a piece of cake. And the world of Star Wars hasn't been the same.