Too much time spent on this game. Because yes, I think I've finally found the worthy successor to Minecraft. More mature, more beautiful, and clearly geared towards multiplayer. So of course, there are some small adjustments needed, but the road is long and full of hope.
If I were to add a few things that have already been mentioned:
The life in the oceans is obviously a bit empty.
An increase in difficulty as you move away from the spawn point to always be on alert, even after progressing far in the game.
Don't touch prospecting, it's perfectly balanced with just the right amount of chance and difficulty in searching for materials!
Maybe rethink the claim system, which works but is cumbersome to implement (command line, not great for multiplayer).
Adding lore, content, lore, content, etc... over and over again.