If the reason to quit is indeed health issues then what can one say. If not then it is very unprofessional of her, especially when there is a rumour that she did it before too.
Anyways may be the new girl would be good too, may be not as good as it was Jiya's second time as Thapki. I remember a show in my regional language where they had to bring in the change of actor for main protagonist coz the girl portraying the character had to concentrate on her studies (she was entering 10th grade). It took a couple of weeks to adjust to the new actor, as we kept comparing her to nikita. But then once she settled into the role, Monisha was so good that it became difficult to imagine that the character was actually played by someone else before her. May be it is too much to expect such an outcome, still I feel we should give whoever is roped in to play the role a chance. Who knows we might start liking this version of ThaRab too.
If Richa Rathore is going to be the new Thapki, I wish the PH do not put her in the same style of dressing and looks as Jiya coz the look that suits one will not suit another. And dressing similarly will be a constant reminder too. May be they could tweek Tap's character too making her a bit more ambitious and less naive. 😉