Though I agree that they dragged the drama, as they do with any other drama; however, I don't think that it was a bad ending. For me, ending at the point when Mahir was being a good husband, and good father by solving all the problems of Mehrus kids was not a convincing ending. When they show Mahir as a person who's too good to be true then it doesn't look believable because it doesn't suit his character in the drama. In contrast, when they show Mehru THAT good then it seems believable because she's a character who's naturally humble and caring, and also got very mature with time. Mehru was nice to everyone from the first day whether it was Durdana Aapa, Ibtisaam, Osama's in-laws, Mahir's family & friend, etc. On the other hand, Mahir is not nice to his only friend who always helped him. Thus, this conflict was mandatory to show how Mahir overcame his inner confusion and became mature.
The last episode had lots of flashbacks but they were necessary because they showed the thought process of all the characters while dealing with this conflict. Here, it is important to note that the thought process of Mahir and Sameen don't show even a single memory of their old days when they were lovers. It signifies that those memories are faded in their minds, they're living in the present, and their decision to marry each other is not because of the love they felt for each other. However, when Mahir took a U-turn to come back to Mehru then he thought about the time they danced together, played together, and celebrated together. It shows that the time he spent with Mehru was not faded in his mind. I like that they didn't unravel either Sameen's mother's hidden motives or Mehru's hospital project to Mahir and the only reason that made him to come back was the loving time he spent with Mehru. I also liked Mehru's decision of not questioning Mahir even after knowing everything as it reminds me of Richard Bach's quote, "If you love someone, set them free. If they come back, they're yours; if they don't, they never were."