I’d say it’s either PvP and Familiars.
Those 2 features are kind of forgotten ngl.
For familiars, you’d have to spend a perk slot to really put them into use (aside Wyvern ofc).
PvP might need a rework. The gems they give is decent, but easily outclassed by other features.
When you wear a Familiar it:
Would be cool if Familiars had a little Attack/Critical/Armor bonus, depending on which Familiar it is.
I have heard that people want Kukuori to buff farming (not mining) because that is the most classic way to get world locks but now when we have fishing ang mining it’s popularity is starting to fade away. Maybe they should decrease seed times or make seeds drop more blocks? Anyways i think that the game is in a good position from that standpoint. 
-Nerpah
how about “every depth while fishing” gets you dumbfish
