According to GalaxyClub’s sources (via TechRadar), it seems that the upcoming Galaxy S9 is expected to maintain the same display aspect ratio of 18.5:9. What this means is that we can expect Samsung to maintain the long-ish design from the Galaxy S8, which we guess depending on who you talk to might be a good or bad thing.
While the display aspect ratio is expected to be maintained, the report goes on to claim that the bezels on the phone will be thinner, meaning that potentially the Galaxy S9 could have a smaller footprint than its predecessor. This should make the phone slightly easier to hold in one hand, if that kind of thing is a concern to you.
This seems to be in line with earlier rumors in which it was suggested that Samsung could further reduce the bezels of the Galaxy S9. Apart from the display, other possible specs include the use of the Exynos 9810 chipset and possibly the Qualcomm Snapdragon 845, which apparently Samsung has first dibs on.