I always dreamed of Sea of Thieves having some kind of Atlantis type cities underwater that you could explore and find cool treasure or stuff in. It could even be something like a active mermaid city or an abandoned one.
And for the diving suits you could find them in the world or there would be one on your ship. The suit would extend the time you could spend underwater. They could look like the old timey diving suits with the huge helmet.
I think this idea could really add a lot to Sea of thieves fun and variety if explored properly.
