Let us remember that Sakura is a main fighter in this, but her main role on a team is as a medic. With that said, whatever limited role she played in the movie had to be split between battle and healing. Her battle scenes were handled typical to her character, but I will comment that her fighting style of dodge and one shot pummel has become more polished. That is to say, she can continuously bob and weave while punching, as opposed to her original style of one strong charge and punch.
Sakura's medical scenes are also handled well because she did the most important medical feat in the movie, which was keeping Naruto alive and recharging his chakra for three days, since this is how long he was knocked out for after Toneri forced a majority of his chakra out of his body, which then exploded and created a hole in the moon. Her medical feats also range into the surgical, as Hanabi had to have her eyes implanted by someone. Lastly she was psychologically necessary, as both Naruto and Sakura both ONLY opened up to her about each other. She was a part of the red string that brought the two together.
Sasuke was shown to be VERY powerful, both in presence and technique, despite the limited scenes he was in. That is to say that in every scene he was shown, a story could be told without any great amount of dialogue. He is shown looking at the very nearing moon at night. He is shown wandering when Sakura mentions about understanding Hinata. He was shown stumbling upon Hiashi who had just run away from surviving a cave in for about three days. He was then shown bringing Hiashi to the village, which was very important to the plot because if Hiashi never made it back in time, no one would know Naruto and everyone else was on the moon and they would not have received the hour time limit for Naruto to save the day before the raikage blew up the moon with a chakra cannon using the harvested chakra of his ninja to launch a time-space bullet (just..smile and nod.) With this said, Sasuke's presence was as it was in the original series; affecting the plot majorly through things he considers a whim.
Strength wise I will say this. It was not only Lee that destroyed half of that comet. There was a team of about six taijutsu ninja that launched off in that green chakra cloak to destroy the meteor, Lee just happened to be the one to launch the final straw that broke the camel's back on only half of the comet. Remember this when I say that Sasuke then proceeded to destroy the entire other half of the meteor with only a chidori. By destroy I don't mean that it broke into pieces. Sasuke essentially erased the meteor half from existence with his chidori. He also appeared, had time to look at Kakashi and give an arrogant speech (saying that when Naruto is not there HE will protect the leaf, slyly telling Kakashi that he is stronger than him,) and disappear before ANYONE else there saw or knew what even happened, not even Gai. So Sasuke fans can appreciate that.
On topic, Sakura was very useful in all facets of her presented characterization (older sister matchmaker for Naruto and Hinata, able to hold her own in battles deciding the fate of the world, and being a miraculous medic.)
