DemsMaShoes
LE

In my untutored opinion.The critic's complaint about the painting is that he feels it doesn't capture the smile and cheerfulness of Kate as she actually is.
He provides some photos as examples of how he feels she should have been portrayed.
To be honest, in the painting Kate looks a bit tired, although there is a slight hint of a smile. This is in contrast to how she usually appears in photos where she looks as if she can barely restrain her boundless energy.
I won't criticize the artist on this matter however, as I don't know if there are traditional stylistic requirements for a royal portrait which precluded it. A more life-like representation may have resulted in the portrait looking out of place when set alongside other royal portraits going back centuries. The artist may have compromised with a slight hint of a smile.
In other words, the criticism of the portrait not capturing her true spirit may be valid when viewing it as a stand alone piece of art. However, this may not take into account the context of the portrait needing to fit in when hung alongside other royal portraits.
If I have any complaints about the portrait it's about William having his hand in his pocket. Ten extras for that man!
It has a child like quality; as if painted by a 12 year old.
It's a shit painting.