I suggest the Pokemon Centers be visually-appealing structures that spawn commonly at any altitude in the dimension. Might even function as an air bubble. They would contain a healer, a nurse/doctor, and a PC.
Here's the reasons why I feel this should be incorporated:
- The Drowned World has hardly any structures, especially in 1.16 where the prismarine structures (which still weren't enough in my opinion) were replaced with large chunks of stone. Frankly, it's rather boring. Apart from containing Drowned Pokemon, the whole dimension can currently be summed up as "A dimension containing large rocks and filled with water that changes between black, blue, and red depending on biome". That's it. Even in 1.12 I felt there needed to be more visual features. The Pokemon Centers could add more detail to the dimension, especially if they have cool and interesting designs.
- Completing the Drowned Lugia quest can be tough on the team. You have to defeat several Pokemon, then challenge a powerful boss with a good Ability. While the addition of Revenant and the changes to the boss system may allow you to put up more of a fight rather than get hopelessly swept, you are still very likely to loose. And run out of healing items, which you can't get more of in the Drowned World. Lower level players may have trouble healing after beating the regular Drowned Pokemon. Completely leaving the dimension for this is quite inconvenient. It would be nice if you could visit a Pokemon Center to heal up your party without leaving the whole dimension.
- What if the player realizes that they need to adjust their strategy? This may particularly affect new players who don't know about Revenant. The Pokemon Center would have a PC that players can use to change up their team.
If you want, the doctors in the Pokemon Center may have a unique skin based on the Drowned Mob or Drowned Pokemon so they look more like Drowned World residents.