The ocean floor is too flat and lacks terrain variation (hills, valleys, and elevation changes). Additionally, the spawn rate of shallow areas (shoals) is excessively low. These issues make the ocean biome feel unnaturally empty and monotonous.

Tectonic DataPack

Vanillan

Will address this once I can toggle on blending to existing worlds.

Ocean terrain overhaul will be included in Tectonic 2.5!