The apt meaning of rishta tv show is "What is the name of this relation" and that can be explored a lot if the illegitimate child becomes the legacy FL
*Identity crisis of the FL questioning her identity with her relations (the Goenkas, the Poddars etc.)
*Her relation with her mother if Abhira becomes her foster mother can be a theme which can be explored.
*Her relation with her step/cousin sister which is Abhimaan's biological child can be explored.
*Her relation with the ML who will be also the ML of Abhimaan's biological child can be explored
So in short the true meaning of this show will fall into place with the next season if the illegitimate child (if it's a girl) becomes the legacy FL.
For a change, the biological daughter of Abhimaan can be the PL like they did with Vinayak in Ghum post leap where he was turned negative.
P.S. These are just my thoughts, please don't throw chappals at me for saying this
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