If this were a one-off then I'd heartily agree with you. However it's our seventh (I'm having trouble believing that! :o ) so by now the central swathe of the country would be suffering from serious overuse!
By moving around like this we tend to give new people a chance from the local areas while giving the long-distance merchants a chance to point their cameras somewhere new.
Our last Gathering but one was Ross on Wye, which is not all that far from Brum, but we've not yet hit the North East...!
All the best,