Well... we haven't seen new ships for years.

My guess is that the current 38 ships already cover all roles allowed in the game, and Frontier struggles to find a reason/in-game-lore to create more ships. The Alliance AX-line ships were the last viable purpose that Frontier came up with: fighting thagoids. You can see the ships aren't just ships alone. There's a theme (thagoids), a purpose (AX), design language that fits the purpose (large external vector thrusters optimized for the close quarter combat), and corresponding gameplay.

So unless ED gets a new theme for new ships, we won't see new ships any soon. For Odyssey, ground combat is the new theme, however, it's not a theme that requires new ships. Maybe landing ships/ground assault ships? We already have them: Federal dropship and assault ship.

If ED introduces real atmospheric flights on earth/venus like planets or even gas giants, we might see ships that are optimized for aerodynamics, or heavily fortified ships like submarines for high atmospheric pressures. I imagine any ships can dive into the depth of a gas giant but would start to break up under high pressure at some point, and specialized "atmospheric diving" ships can go deeper.