I guess when I look at the number of engagements her father-in-law and Anne, Camilla, the Queen, Sophie (who has kids) does, sorry but what did she do? Stop stepping on eggshells there are those of us out there who have worked hard with and without children, I don't care that she is in the public eye. So what! She chose this life, she chose this when she agreed to marry Wills, so live it. No excuses, she has had time to 'learn' the role, practice and have access to those in the know.
BTW the Queen never expected to have to step into her role so quickly, but unfortunately her father died. She was then thrown into the role, while mourning, with young children, it would have been tough. Kate has the luxury of time on her hands, how long we don't know, but time. I don't think it is being nasty to say, use the time to learn.