It's no real secret that the aim with the Samsung Galaxy S9 was to take every facet of what the Galaxy S8 was and improve upon it in subtle ways, and Samsung has authored a post wherein the teams behind the new flagship speak out about what inspired them to iterate on the Galaxy S8 in the ways that they did. Since the larger Galaxy S8 Plus and Galaxy S9 Plus have the same relationship, of course, it's safe to assume that the same conventions and thoughts apply, for the most part.
According to Taihoon Kim in Global Product Planning for Samsung, the aim with the Galaxy S9 was to make full-experience improvements that would come together to create a better, more coherent product and user experience. Wonhyung Cho of the same group spoke on the matter of AR emojis, saying that the new feature was aimed at allowing users completely personalized communication. Junmo Kim, meanwhile, said that the aim of the Galaxy S9's camera, including its app, was to encapsulate the best user experience in the simplest interface possible, while leveraging the full power of the phone's superior camera setup. Jaehyun Kim stated that Samsung got together with HARMAN and Dolby Atmos to create the most immersive sound experience possible, helping to tie the whole user experience together. Jaeho Balk said that the phone's physical design is the result of listening to feedback, both positive and negative, about the Galaxy S8, and making small changes to optimize the design; essentially, when it comes to physical design, the Galaxy S9 is what the Galaxy S8 should have been, with slimmer bezels, better-hidden sensors, and more durable glass.
Three designers from the UX group said that the aim with the Galaxy S9 was to drive a simple, customizable, efficient experience without compromising on the beauty and rich feature set that Samsung's user interfaces have always been known for. Application Product Management group member Martin Lee said that partnerships and improvements have made Bixby the most useful it's ever been, and the team is still exploring the possibility of new features in the future. Nayoung Kim of the Global Product Planning Group said that most smartphones these days are satisfactory, so the focus with the Galaxy S9 fell not to how varied the feature set was, but how satisfying each individual feature was. Finally, Taihoon Kim chimed in to add that the team will look to AR and AI, among other features, to maintain a superior feature set for Samsung phones going forward, and will plan their rollouts and device releases to divert consumers' attention from other devices on the market.