One thing I noticed was that open-heartedness is a recurring theme in "Emma", also. Emma cannot like Jane Fairfax because she is so reserved, and Mr. Knightley praises an open temper in a wife. I wonder if this is a quality that JA came to value more as time went on?

On the other hand, I have to agree with Helena 6 that Anne herself seems extremely reserved, perhaps for reasons that are not her fault, but still, she is. In fact, the whole novel seems to be blanketed in excessive reserve, IMO! Perhaps Anne particularly values open-heartedness because she knows it's a virtue she doesn't possess?