Personally i think they are quite arousing; they seem to me that they look quite soft, the wrinkles alone look amazing and the rest of her feet. I would assume that they would be a 10 on a ticklish scale.
Wrinkles are a big sign that they might be ticklish, but I've done some women with wrinkles who weren't.
Thats when I rely on my EXTRA SENSORY TICKLISH PERCEPTION or E.S.T.P...it never fails...lol