This made me look up a full performance from his tour and I think his vocals overall are not the problem (what surprised me because I really don't like his "studio" voice. His natural singing voice is so much better.) He's doing just fine if he sticks to the original melody. HOWEVER, his ad-libs need drastic improvement! In the video that I saw they were bearable but he takes it too far in this video.
Try to watch this with a straight face all the way through.
