As a Roblox developer, it is currently extremely difficult to achieve decent-looking water in oceans. The basic sine waves we are given with the current terrain water does not look realistic in large bodies of water.
The slider for WaterWaveSize should change the water formation with different values. Larger wave sizes should start to develop white caps with more complex shapes seen in oceans in real life, becoming more prominent with higher values closer to 1.
These taller waves would look closer to the water in Sea of Thieves:
Smaller wave size values for scenes like pools would continue to look closer to how they do now because terrain water already looks great in those applications.
Thanks for reading!