As far as having the fest in a central location, I can tell you that Jim has told me that it is always on the coasts in order to accomodate the actors and to save on Jim's expense of flying everyone to a central location, since most of the stars live on the coasts. ...
I think it's all about expense and accomodating the stars
Yes, absolutely, that's the reason the Fests are held in NY or in SoCal. That's where the actors live. In California, especially, it allows us to have in "drop in" guests who come in for a day or for the afternoon but don't have to commit to travel and several days away from home.