If you are not aware yet, Comic Con will stay in its long time residence of San Diego. There was some speculation that the convention would move to a new location like Anaheim or Los Angeles. However, it has been officially announced that the west coast Comic Con will remain in San Diego up to 2015. San Diego won the bidding war over other California cities in order to keep the convention in one spot.
Los Angeles isn't a bigger venue. And the Anaheim convention center isn't either, but they have so many surrounding hotels that are close enough to host events that it would end up being larger than what San Diego has. It's only staying at San Diego for 5 more years. After that who knows if San Diego will be able to keep up with the popularity.