Itachi did the same thing to Sasuke. There is nothing romantic about it. Unless you think Itachi had incestious feelings towards Sasuke.
Again, if they were a couple they would have kissed instead.
Anyway if you know how to interpret the scene. Itachi is the most important person to Sasuke the fact he share a personal gesture between he and his brother with Sakura show she is now important to him
Itachi is Sasuke's brother, not the Sasuke's wife who he will have a children in the future
Kishimoto didn't showed any interaction between Naruto and Hinata in Canon Manga after 615. They already appeared together with children in 700 without any previous interaction.
Even Hinata and naruto didn't had any Kiss in manga. Their biggest interaction in manga is the holding hands.
Kishimoto prefered to show NH kiss in the movie.
Again This a shounen manga. This isn't a shoujo to show a romantic Kiss.
Why he will show SS kiss in the manga when the own protagonist didn't kiss Hinata in manga?
Sasuke already finished the last chapter in manga with his closure with Sakura and with his own monologue.
Sasuke will be the true protagonist.