The last scene is a true testament to how Yuna has grown throughout this game. Think of how Yuna was at the end of FFX. She was strong, but she was also very weak in many aspects of her personality and her life. When we last saw Yuna and Tidus together, Tidus said he had to leave, and Yuna ran after him only to fall through him, realizing what he really was. She couldn't even look at him jump off the airship and into the ocean, but could only say "I love you," not even to his face.

Skip ahead, we have a new Yuna. Yuna is presented with the possibility that Tidus might still be a dream, and that she might lose him again. The old Yuna would have clung to him and not let go until there was no choice. But the new Yuna.....not only did she have the confidence that he would stay, she actually tested it herself. When Tidus left Yuna, he jumped off a "ledge" and into the water where he disappeared. Now, Tidus is saying that he might still not be real and that he might disappear again, so Yuna recreates the scene from the past. She pushes him into the water, just like when he disappeared last time. And he didn't. Not only did she have the courage and brevity to do this in the face of the possibility that he actually might disappear, but she did it with a smile, having the optimism and confidence that he wouldn't. And in doing so she gave Tidus that same feeling. She has changed.

Getting the perfect ending wouldn't have seemed like such a hassle if getting the good ending wouldn't have been so easy. It should have been harder to get the good ending, then there would have been some balance to the situation. I however liked the perfect ending, but as I say to everyone, you shouldn't kill yourself over it.