I think this is the stage set for change. We see Emma's character weaknesses here. We know Emma has room for growth.

I thought Mr. Knightly was expressing his frustration on the role reversals that placed Emma as the caretaker making the family decisions and her father and governess accepting and praising these decisions. Not everyone gets a fair share of their childhood. Emma is priviledged, but a loss of a mother early, and a sickly father stole much of her childhood away.

Only Mr. Knightly appeared to see Emma as a child in need of guidance and a strong word here and there. However, Emma is 21 years old and an adult. As an adult, Emma must work through her own problems.