For me, I don't mind a single Mauli, because it takes a lot of strength to be a single mother. Mauli is already shown to be a strong, independent, fierce woman who fights battles head on and comes out stronger.
So showing her as a single mother (which she has been for the past 6 years or so), wouldn't be a horrible ending.
But from everything they have shown post-leap, I cannot pinpoint if she actually doesn't love Ishaan or if she's too scared to fall in love again from everything she has endured.
The first few episodes after the leap, I assumed she was slowly falling for Ishaan.
But when Kunal came back and all her pre-leap memories came back with his arrival, and all the flashbacks, and the whole camp track/her getting drunk at this birthday dinner and getting emotional about the EMA made me re-think that she is still struggling with her feelings for Kunal and that is what is holding her back from loving Ishaan or anyone really.
So I would like that aspect of her character to be worked on. Because in my opinion, for her to truly rise above it all she should conquer her fears and insecurities instead of running away from them like she has been doing - by closing herself off at first towards Kunal, then towards love/Ishaan.
Marrying Ishaan would be icing on the cake. But if they just showed her heal through her hurt, accept that she loves Kunal but that doesn't mean she wants to be with him, show that she is able to trust men/love again, etc. and then she chooses to stay single, then I think that will be the second best alternative, if there is no Ishaali wedding.