On the basis of the standards of the festival generally (including the sound) and the performances of the artists in particular I don't think that the committee need to worry about selling tickets for the next festival.

Personal likes and dislikes with respect to artists and their material will always generate comment, but Shrewsbury has shown that it fully deserves its place as one of the top festivals in the U.K.

(and I have to say that organising a festival is not a job that I would take on, for money and certainly not for love).