I think a lot of attendees are hoping to see special events this year that are unusual or bigger. GenCon is always a good time - but opportunities to do more are there.
Speakers/Panelists/Book-Signings: Seriously try to get people like George RR Martin, Neil Gaiman, Tracy Hickman, D&D Alums like Greenwood, Cook, and Mearls to speak and do signings at the con.
Talk to the board game companies and help them do more championship tournaments (Steve Jackson Games for Munchkin, Z-Man for Pandemic, etc.).
Big interactive events are a great draw (Novo Ordus's CoC is amazing) - picture 8 table Paranoia events or a Hackmaster Open (essentially a Hackmaster version of the D&D Open). Encourage Paizo to do some special things would be good.
True Dungeon already has their modules designed (and likely partially built) but having GenCon have a scavenger hunt or similar to get unique True Dungeon tokens would be cool and very fitting.
Bigger charity auctions separate from the main auction - they would just get lost. Have Baldman auction off D&D AL certs or get Paizo to do the same for Pathfinder, etc.
Of course - with Lucas Oil stadium being used - a live action game of BloodBowl on the Colt's field would be the highlight of the con!
The smarter game companies will do early releases at GenCon or delay releases to premier at GenCon.
Although GenCon is a great time - we're all hoping the 50th anniversary will be unique and spectacular. Anyone else have some suggestions?
I'd like to see some panels or even just museum-style panels about the history of Gen Con.
I agree with Austicke that I'd like to see a display of some kind celebrating the history of GenCon. Maybe even have some people on the scene doing a documentary?
Felwred, you have some great ideas too! I love how you think big!
The Fight in the Skies Society will be running a special event for the 50th anniversary
What I would like to see is the big premier style events announced BEFORE event registration begins... To many times in the past big events get announced after schedules are pretty much set (the first 1000 player Catan event springs to mind...).
People can advertise what they're going to do in advance of submission but if they don't fill it out in a timely manner Gen Con really shouldn't have to do the run around and constantly keep asking people the status on their submission. Asking if they need assistance or assisting if there's a request from someone I think is okay though.