I think the new doctor will help zashi as to find out as to who is real Indira and for zara to get her memories back. I don't think they create a new love story for LW and doctor.
Even, we are waiting to know what happened in past 8 years and who is real Indira and real zara?
I think that zara must be Indira bcoz of Rishi's strong feeling and that's why CV's have made him say that zara is his love and LW is his responsibility (bcoz of Indu and also on humanity sake).
Though everyone says that LW is Indira, rishi could not connect to her and accept her and there is some big twist here I guess.
We can also remember what shweta said to zara before leaving. She challenged zara- "Whether she can take the place of Indira and win rishi which shweta could not do it till now?". So we can also doubt shweta here.
We wanted CV's to finish this track and give us with some new track.