Yup, you can't please everyone,
I've been to only a few nationals (Trenton, Charlestown, Vermont, and West Bend) and only the Vermont and Trenton rallys have I been able to attend the last day. The others I've had to leave Sat morning to get back home by Sunday evening. I'd like to attend next year's rally in Gray, Tn., but it will be the same situation, leaving Sat. So while I'll have 5 days to get there and can enjoy the trip, getting home means leaving the rally early, so I'm on the fence as to whether I'll attend.
There are always lots of theories, but dealing with customer response metrics all day in my job, theories are worthless. Response by the customer is the only metrics and it is predictable and repeatable given a large enough population. I would said that the test of having a rally far from club members with minimal good riding was greeted with tepid response by the club members. I would predict that next years rally will have very good attendance given its location. Of course the other variable, that we can't really test, is what would attendance be if the rally were held Tues-Thurs.
Oh well, suns shining (finally), time to go for a ride.