Swara's death was left open-ended and they could and should change it, she could want to create problems in the Nal Emporium project as revenge for all AS and the Ranes did to her for 5 yrs... plus, the plot of having been married to Vivek and Athu and the chaos it could cause with the latter alive is just too juicy of a plot to let it go, if they show us a more stronger, decisive, vindictive Swara who doesn't take any crap from anyone.
It would also put once again Kallu in a tough position, because she saw part of what her AS and Vivek did to Swara and Malhar, so Swara's anger is totally justified, but at the same time she'd be tempted to try and get both sides of the family to work thru their issues and forgive (she, at least can't be accused of hypocrisy, because she keeps forgiving and trusting most of the people who've wronged her in her family... she doesn't even hold any grudge against Sarthak and is trusting Sampu of all people!).