as the Douche of Cambridge, the Douchess laughed and pounded him on the back. She didn't just purse her lips and suppress a demure smile. When he asked a Nova Scotia (I think) fisherman what a particular part of the lobster was called, and the answer was ".....but we call it s...t", his bride laughed as heartily as everyone else (while William blushed). I'll bet she has a great sense of humor.
She obviously charms everyone she meets, and she has charmed William for the better part of ten years. Like HM, she has the ability to turn a bland and dignified face to the world in general. That's what is required to enjoy a long and successful life in the public eye if you're a royal. The late Princess Margaret was never very much in control of her emotions, nor was Diana.
Those of us who only 'know' her from the telly and the tabloids can't presume to analyze her and pronounce her boring. I don't have any gut feelings about her, or about anyone else I don't know. From what I am actually able to observe, she seems to be an elegant and gracious addition to the BRF.
PS- it would appear that the newlyweds are madly in love, so that can't be bad.