Jones's problem- much like Elvis's- was a lack of artistic judgement. Left to his own devices he'd have been a rocker not a pop star (and possibly still playing the pubs of South Wales). He has drifted in and out of cool at the direction of his managers.
Jones latest material is secular gospel- conscience-jerking songs about how one should live one's life- only without any mention of Jesus. At first I thought I was quite impressed with them and then I discovered I couldn't be doing with the preachiness.