Have some security cameras on at night if the areas will be unattended. They are very inexpensive nowadays. It would be nice to catch the thieves instead of simply closing the hall.
I don't have any suggestions for the tournament area because I don't participate in any of it. I'm just there to meet people and have fun in a less intense setting. The seminars are good although some are better than others. The overall format of the show is good.
There should be better organization of the free play area ahead of time though. Maybe have reservations. I brought machines last year and they sat out in the hallway most of the show. This year I didn't being any because of how bad last year was and I live only 8 miles away from the Westin. Establish some rules and stick to them.
It would be nice to use a secondary overflow game room for all non-functioning machines and "projects" that are for sale. Maybe a flea market or swap-meet type setup for games only?
Nothing deters me more from bringing games than to have the ones I brought sitting out in the hallway behind the free play area out of sight and unprotected while there are several machines that are either out of commission or were non-functional "projects" that have no business being in the free play area in the first place. If they are not going to be repaired move them out if there are others waiting to get in. This year wasn't an issue but it was the year before. I think it would be nicer to have too many than not enough.
Otherwise I like the Expo but it has become a one day thing for me anymore. After one day I've seen all there is to see there. I usually meet friends at the show and invite them to my pinball "mancave" afterwards for open bar and ice-cold beer on tap and that about wraps it up.