If I were in charge (I'm not), I'd break up the layout repeated every year. For example, the tech and historical sessions seem to be popular but not as accessible or visible. They could moved to one of the main exhibition halls or to the large "For Sale" hall that's usually 1/2 filled with for sale cars. The other exhibit hall would fit most of the vendors. General purpose tech sessions might prove popular too (paint and body work, paint repair and detailing, dentless body work demo, etc.).
Another idea would be to use the main parking lot for something; like a 2-day swap meet or tech contests (e.g. team competitions to strip a chassis down to the tub (or in reverse), D&A Weber carbs, setup and run, RC/go cart races, for sale cars instead of in the dimly lit hall, model car/train/truck vendors, etc.).
And if things were really desperate, there's always the county fair gaggle of pots and pans, squeegee, chamois, vibration chair exhibitors (segregated of course) to make it a break even event.
And since this event is mainly a guy thing, female mud wrestling, NOPI-type girls and wet Porsche T-shirt contests are always crowd pleasers.
This is why I'm not in charge.
Seriously, Bob has always organized a classy event and I wish him well. It's too bad there will be a void this Sept.
Sherwood