When the movie got released, many complained that they didn't like it for various reasons. But mainly coz of its so called abrupt ending that they didn't like. I think it was misunderstood and even a bit mis-realized at the very first place.
Don't know somebody has thought of it or not, but the blame for this comes down on two things -
<I've removed first point, which is irrelevant to the second point>
2)Marketing: Sadda Haq, yes this song was great and all. But using this song as the prime weapon of publicity was a blunder b'coz the movie was a love story and this song set the mood otherwise.
I heard many people saying that we expected that Jordan would be a rebel against the corrupt system (in the League of Rang De Basanti).
There are no 2 thoughts about it, it was a very personal and intimate movie, but in contrast, Sadda Haq was a totally rebellious and crowd-pulling song and not apt for marketing the movie.
Also, the whole movie was thought of to be presented as Jordan(Ranbir) being the sole driver of the story. But in fact, he was driven by Heer(Nargis) at each step. And as I already said, she was no match to what the role demanded. The movie would have been so better if they would have got an accomplished actress instead of a newcomer. With Ranbir, AR Rahman, Imtiaz Ali and Mohit Chauhan, bars were already very high for this movie, why don't they seriously thought while selecting the main lead actress also, i don't know. They should have given equal weightage to lead actress too.
Then the ending would have been more clear and satisfying. B'coz movie doesn't end with Jordan's life, it ends with Heer's life and explaining "when and where" Jordan and Heer will live happy together, forever.