Darkslinger
Notorious Pirate
We're kind of left in the dark. So all of my regards/concerns might be false.
It might have high-level enemies. If the cave is accessible through King's Run, I might have a problem with it though. The cave system is labyrinthic enough as it is - adding more and more to it will only make it worse.
I believe that the content team should maintain focus on how to restructure the original game world before delving into the topic of additional areas and enemies. The whole game is in need of an overhaul - it'll be harder to achieve that if there's more content to take into account.
Also, I noticed a lot of familiar models in the screenshot. Old devs reused a lot of the game models and textures - hope the mistake isn't repeated this time round.
Before additions like this take place, it would be best if islands were enlarged. This would lead to islands that contain multiple different biomes, areas and enemies which are accessible without the restriction that is loading screens. The caves and woods could all be implemented as part of one large 'unlimited' island. The 'new' islands could also include animals, collectible materials in the environment, and enhanced villages and towns with multiple NPCs.