I think the casting is pretty good. Gautami is doing a fabulous job and really looks like a mother of 2 school going kids managing the best she can in a difficult situation. She comes across as this bubbly fun loving character who also knows how to laugh and enjoy and not just cry.
And I give credit to the writers for showing how difficult it is for her character to deal with a complicated situation of loving someone but still being unable to acknowledge because of so many other parameters. She has not even told Ami, Khusboo and Baa yet and it can only be imagined how Ami will react.
What I would expect from Sanjay is to be more understanding of her situation instead of forcing her to acknowledge her love and get engaged asap.
I also hope they show a little more of the impact that news will have on Khusboo too since although she does not throw tantrums like Ami, it does not mean that she is not affected by her father's suicide, mother's remarriage etc. Infact being more emotionally mature than Ami, she would probably realize the implications better (going and living in Prabha's house which I'm sure she'll hate) on her mother and the family overall.
I think the story has a lot of potential if they stay true to the original storyline and don't lose it by focusing too much on Sanjay's family and their problems. I would prefer to see more of the Joshipura household with their bitter sweet moments.
And they do have some great actors in Manav, Gautami and rest of the cast so hopefully the storyline will do justice to both their acting potential and the concept overall.