Pooja's track is inextricably tied to so many other characters: Shubha, Vinny, Mrindula, Trisha, Vasu, Kamini, and Karan. Because of Payal's actions, they are also going to be affected. Harsh and Kamini will probably be forced to exit the show as their roles depended on Pooja. Megha Gupta's character was probably brought on board to help Pooja in some way, so she is no longer needed. I think the only reason they introduced this Shivangi character is because Mrindula no longer had a role without Pooja. Vinny and Shubha are left up in the air for now, and Vasu and Trisha can't continue without them. In Sony's defense: Other shows have these ridiculous and far-fetched stories that take full creative license ignoring facts and creating impossible circumstances (people coming back from the dead, getting "plastic surgery," ghosts, God coming to earth, etc), so it is easier to cope when an actor quits. It doesn't have to be logical. In this show, there is more pressure to come up with a logical explanation within a limited amount of time, so I can see how it would be difficult to do when an actress like Payal quits at the climax of her character's story. However, having said that, they should just replaced her.
I think you hit the nail on the head KS. We watch LS for a compelling, realistic, and modern storyline...not due to the fanaticism towards certain actors, or a glamorous on-screen pairing. Other soaps have switched out or even killed off their lead actors and actresses, despite having some very passionate fans. Sure fans complain about it at first and threaten to stop watching, but they all get over it eventually. With LS, I don't think anyone would even care of Payal had been replaced because we are not interested in Payal, we are interested in her character's story. Instead of casting Sreejita as a new character, she could have replaced Payal. i'm not fond of her track so far. It doesn't seem to tackle the same kind of issues as the others or have the same depth. Pooja's story was an inspiration. It showed that a woman can find strength and courage to defend herself, and that she does not have to bow down to an abusive relationship. It even showed that a divorced woman can still find love and happiness. Geeti's track could have been much more compelling if the outcome wasn't such a fizzle. And I actually did find Mrindula to be a potentially interesting character, if only because of her disinterest in marriage. That is not something we commonly get to see in soaps. Instead we hear the same old dialogues about how a woman's happiest moment is when she gets married. A woman's greatest happiness is the birth of her child. As someone who also has no interest in marriage, it was refreshing for me to see my own perspective finally get some acknowledgment.
Unlike useless shows like Choti Bahu and Maayka, where the characters start out weak, continue to be weak throughout the show, and end up weak with absolutely no depth or personal growth, Pooja's character has developed significantly over time. She has gone from being meek, fearful, and docile to being a woman of great courage and strength. It's too bad they didn't see this transformation through.
Unfortunately I find LS to be increasingly unpalatable. It is deeply disappointing, as this is the type of show I have been waiting for and there will be nothing else quite like it. If Choti Bahu ended, I wouldn't care, because whatever show comes to replace it will no doubt be exactly the same, but this show is absolutely unique and irreplaceable.