i wanted to address a few points:
1) i have not seen her in any other show and do not know her as a person so i can not compare siddheshwari to ridhima or any other character she has played. i think she is doing really well as siddheshwari. The character is believable and realistic.
2) Being the antagonist does not mean the actor/actress is wasting his/her time or the role is not good enough for him/her. Some of the best and most accomplished actors have played villains (can't remember any off the top of my head).Everyone loves a hero, because that's easy to do. But if everyone loves to hate the villain, then the villain is doing a great job.
3) For Sukirti to be an accomplished actress, she needs to avoid being type-casted or playing one time of character all the time (she can't always be a sweet, love able girl). She can only last so long as ridhima, her character. Sukirti has to become independent of her characters and be known for her acting, not just the characters she has played. Sukirti can not be Riddhima forever or her acting career will be very short lived.
Right now I am thinking about Prachi Desai (Bani from kassam se). She is trying to move onto the big screen but I do not think she will be very successful because waaaay too many people know her as Bani and cannot, or will not see her as any other character. So she's stuck as the bahu in the public's mind and cannot move past that as an actress.
4) Sukriti's character, Siddheshwari is not the lead in this show but that does not mean she is any less important. If a less talented actress was to play Siddheshwari, the character would fall flat and look weak.
so those are my four cents 😃