It is true that a portrait need not look exactly like its subject to be a superb portrait. Some highly individualistic painters manage to make all their subjects look as though they belong to the same family, yet still catch the vital character of the individual.
This is not one of those portraits. It is shockingly bad. The eyes, whilst reasonably close representations of Kate's, look slightly stoned. The nose, instead of being coquettish, has become slab-like. And the mouth! What was he thinking? This is a smug smirk, as if to say: "See? I told them I'd get him. Now I'm going to be Queen, so there!"
And, as a final insult to aesthetics, he appears to have put a vaseline glaze over the whole horror show, like a Penthouse Pet of the 1970s.
This is bad. Really bad.