i think when u criticize her, do it in a postive manner.. she will understand you better and wont even realize ure telling her to do something in a diff way...
when she tells you what she has heard from ure mom or sis, backbiting bout her, support her and say u understand where she is coming from.. sometimes thats all that matters. your become her support system and show her that she can count on u and that even though you may be a son and brother, u are her husband too, and very much her own.
jub thak apniyat nahi hogi, dooriya rehengi :)
but its great that there have been positive changes... just keep working on it.. good luck!
all the things you have said, I have tried already :)