George Lucas does not approve anything personally, however EVERYTHING that is Star Wars EU, from books to comics to cartoons to action figures is ALL approved or disapproved by his staff at Lucasfilm. Star Wars is his baby and they watch over it VERY closely, they are VERY nitpicky about technical things, IE: one of the novels had Luke saying "that's ok, I only need one hand to fly an x-wing". Lucasfilm sent them a footnote that said "two hands" and it had to be corrected before it could be published. Now the reason EU is not considered "canon" is because as picky as Lucasfilm is, they also give the authors a lot of freedom when it comes to storylines, characters, developements and even time frames. They consider that stuff to be part of the writers' creativity and they try not to impose on that if they don't absolutely have to. So, you get a lot of writers who are doing Star Wars and none of them know what the others are writing and they contradict each other left and right on stories, characters and time frames and wala, the EU has no credability.