The E3 Expo management has issued a survey to some attendees that includes some questions about adding a new conference segment to the proceedings. The questions attempt to gauge interest in having "a conference program covering multiple industry topics, including panel discussions with industry leaders, at future E3 Expo events."
Further questions narrow down potential topics, including "Interactive Entertainment Business trends," Game Development," "Game Career Development," and "New Product Demonstrations." Of course, querying attendees about this is by no means a confirmation that E3 will include panel discussions in the future, but it is an indication that the organizers are thinking about it. Adding what amounts to GDC-style content to the generally marketing-focused E3 would be a significant change in focus for the expo -- an event that just can't stop changing.