(SPOILER)I can see, but I really liked how this game did not end all that happy. I liked seeing Joel finally speaking about his Daughter, I loved the overall feeling of dissatisfaction from Ellie And Joel with how everything turned out, and I loved the desperate struggle from the Fire Flies failed research.
It was too brief I agree, but I felt handled well enough. I think the ending is just kind of the victim of not living up to expectations, especially not after Winter. I don't know if the game really had a chance at following that up. 
So far, the two people who have made it through Winter seem to think that was the highlight of the game, so the rest of you? Look forward to it.