I think Bajaj will have more children or who will make Prerna's life difficult or play kitchen politics with her? Bajaj is 44 so he probably will have older children who will be introduced after the marriage.
To be honest only with Bajaj, Prerna and Sneha there isn't much they can explore all Bajaj does is talk about business all day and Sneha already likes Prerna so there isn't much scope for drama with that. If there are older children Prerna's relationship with them can be explored and it can be shown how they gradually come to love and respect Prerna as their mother just like they showed in season one.
Once Bajaj dissapears/frees Prerna from the marriage in 4/5 months time and Anupre marry it will be interesting to watch how the kids and Prerna miss each other and the changed dynamics in their relationship. It's Anu's turn to leave Prerna and marry Aparna next time they reunite so it will be good to watch how Bajaj and his children mentally and emotionally support Prerna in such a bad phase. So I am all in for Bajaj having older children.